diff --git a/core/ClassInfo.php b/core/ClassInfo.php
index 39baa1765..7aa17fa56 100644
--- a/core/ClassInfo.php
+++ b/core/ClassInfo.php
@@ -231,6 +231,25 @@ class ClassInfo {
 
 		return $matchedClasses;
 	}
+
+	private static $method_from_cache = array();
+
+	static function has_method_from($class, $method, $compclass) {
+		if (!isset(self::$method_from_cache[$class])) self::$method_from_cache[$class] = array();
+
+		if (!array_key_exists($method, self::$method_from_cache[$class])) {
+			self::$method_from_cache[$class][$method] = false;
+
+			$classRef = new ReflectionClass($class);
+
+			if ($classRef->hasMethod($method)) {
+				$methodRef = $classRef->getMethod($method);
+				self::$method_from_cache[$class][$method] = $methodRef->getDeclaringClass()->getName();
+			}
+		}
+
+		return self::$method_from_cache[$class][$method] == $compclass;
+	}
 	
 }
 
diff --git a/core/Config.php b/core/Config.php
index 6bc413be3..4cf55611b 100644
--- a/core/Config.php
+++ b/core/Config.php
@@ -173,12 +173,6 @@ class Config {
 		$this->collectConfigPHPSettings = false;
 	}
 
-	static $extra_static_sources = array();
-
-	static function add_static_source($forclass, $donorclass) {
-		self::$extra_static_sources[$forclass][] = $donorclass;
-	}
-
 	/** @var [Config_ForClass] - The list of Config_ForClass instances, keyed off class */
 	static protected $for_class_instances = array();
 
@@ -371,14 +365,17 @@ class Config {
 
 		// Then look at the static variables
 		$nothing = new stdClass();
-		$classes = array($class);
+
+		$sources = array($class);
 		// Include extensions only if not flagged not to, and some have been set
-		if ((($sourceOptions & self::EXCLUDE_EXTRA_SOURCES) != self::EXCLUDE_EXTRA_SOURCES) && isset(self::$extra_static_sources[$class])) {
-			$classes =  array_merge($classes, self::$extra_static_sources[$class]);
+		if (($sourceOptions & self::EXCLUDE_EXTRA_SOURCES) != self::EXCLUDE_EXTRA_SOURCES) {
+			$extraSources = Object::get_extra_config_sources($class);
+			if ($extraSources) $sources = array_merge($sources, $extraSources);
 		}
 
-		foreach ($classes as $staticSource) {
-			$value = Object::static_lookup($staticSource, $name, $nothing);
+		foreach ($sources as $staticSource) {
+			if (is_array($staticSource)) $value = isset($staticSource[$name]) ? $staticSource[$name] : $nothing;
+			else $value = Object::static_lookup($staticSource, $name, $nothing);
 
 			if ($value !== $nothing) {
 				self::merge_low_into_high($result, $value, $suppress);
diff --git a/core/Extension.php b/core/Extension.php
index 7eb2a8ce7..70072616f 100644
--- a/core/Extension.php
+++ b/core/Extension.php
@@ -46,14 +46,11 @@ abstract class Extension {
 	/**
 	 * Called when this extension is added to a particular class
 	 *
-	 * TODO: This is likely to be replaced by event sytem before 3.0 final, so be aware
-	 * this API is fairly unstable.
-	 *
 	 * @static
 	 * @param $class
 	 */
 	static function add_to_class($class, $extensionClass, $args = null) {
-		Config::add_static_source($class, $extensionClass);
+		// NOP
 	}
 
 	/**
diff --git a/core/Object.php b/core/Object.php
index b37423762..1b7f98a07 100755
--- a/core/Object.php
+++ b/core/Object.php
@@ -463,6 +463,7 @@ abstract class Object {
 		if($subclasses) foreach($subclasses as $subclass) {
 			unset(self::$classes_constructed[$subclass]);
 			unset(self::$extra_methods[$subclass]);
+			unset(self::$extension_sources[$subclass]);
 		}
 
 		Config::inst()->update($class, 'extensions', array($extension));
@@ -505,6 +506,7 @@ abstract class Object {
 		if($subclasses) foreach($subclasses as $subclass) {
 			unset(self::$classes_constructed[$subclass]);
 			unset(self::$extra_methods[$subclass]);
+			unset(self::$extension_sources[$subclass]);
 		}
 	}
 	
@@ -531,38 +533,66 @@ abstract class Object {
 	
 	// -----------------------------------------------------------------------------------------------------------------
 
-	private static $_added_extensions = array();
+	private static $extension_sources = array();
+
+	// Don't bother checking some classes that should never be extended
+	private static $unextendable_classes = array('Object', 'ViewableData', 'RequestHandler');
+
+	static public function get_extra_config_sources($class = null) {
+		if($class === null) $class = get_called_class();
+
+		// If this class is unextendable, NOP
+		if(in_array($class, self::$unextendable_classes)) return;
+
+		// If we have a pre-cached version, use that
+		if(array_key_exists($class, self::$extension_sources)) return self::$extension_sources[$class];
+
+		// Variable to hold sources in
+		$sources = null;
+
+		// Get a list of extensions
+		$extensions = Config::inst()->get($class, 'extensions', Config::UNINHERITED | Config::EXCLUDE_EXTRA_SOURCES);
+
+		if($extensions) {
+			// Build a list of all sources;
+			$sources = array();
+
+			foreach($extensions as $extension) {
+				list($extensionClass, $extensionArgs) = self::parse_class_spec($extension);
+				$sources[] = $extensionClass;
+
+				if(!ClassInfo::has_method_from($extensionClass, 'add_to_class', 'Extension')) {
+					Deprecation::notice('3.1.0', "add_to_class deprecated on $extensionClass. Use get_extra_config instead");
+				}
+
+				call_user_func(array($extensionClass, 'add_to_class'), $class, $extensionClass, $extensionArgs);
+
+				foreach(array_reverse(ClassInfo::ancestry($extensionClass)) as $extensionClassParent) {
+					if (ClassInfo::has_method_from($extensionClassParent, 'get_extra_config', $extensionClassParent)) {
+						$extras = $extensionClassParent::get_extra_config($class, $extensionClass, $extensionArgs);
+						if ($extras) $sources[] = $extras;
+					}
+				}
+			}
+		}
+
+		return self::$extension_sources[$class] = $sources;
+	}
 
 	public function __construct() {
 		$this->class = get_class($this);
 
-		// Don't bother checking some classes that should never be extended
-		static $notExtendable = array('Object', 'ViewableData', 'RequestHandler');
-		
-		if($extensionClasses = ClassInfo::ancestry($this->class)) foreach($extensionClasses as $class) {
-			if(in_array($class, $notExtendable)) continue;
-			if($extensions = Config::inst()->get($class, 'extensions', Config::UNINHERITED)) {
-				foreach($extensions as $extension) {
-					// Get the extension class for this extension
-					list($extensionClass, $extensionArgs) = self::parse_class_spec($extension);
+		foreach(ClassInfo::ancestry(get_called_class()) as $class) {
+			if(in_array($class, self::$unextendable_classes)) continue;
+			$extensions = Config::inst()->get($class, 'extensions', Config::UNINHERITED | Config::EXCLUDE_EXTRA_SOURCES);
 
-					// If we haven't told that extension it's attached to this class yet, do that now
-					if (!isset(self::$_added_extensions[$extensionClass][$class])) {
-						// First call the add_to_class method - this will inherit down & is defined on Extension, so if not defined, no worries
-						call_user_func(array($extensionClass, 'add_to_class'), $class, $extensionClass, $extensionArgs);
-
-						// Then register it as having been told about us
-						if (!isset(self::$_added_extensions[$extensionClass])) self::$_added_extensions[$extensionClass] = array($class => true);
-						else self::$_added_extensions[$extensionClass][$class] = true;
-					}
-
-					$instance = self::create_from_string($extension);
-					$instance->setOwner(null, $class);
-					$this->extension_instances[$instance->class] = $instance;
-				}
+			if($extensions) foreach($extensions as $extension) {
+				$instance = self::create_from_string($extension);
+				$instance->setOwner(null, $class);
+				$this->extension_instances[$instance->class] = $instance;
 			}
 		}
-		
+
 		if(!isset(self::$classes_constructed[$this->class])) {
 			$this->defineMethods();
 			self::$classes_constructed[$this->class] = true;
diff --git a/model/DataExtension.php b/model/DataExtension.php
index b2dae0611..d975f7db2 100644
--- a/model/DataExtension.php
+++ b/model/DataExtension.php
@@ -31,34 +31,21 @@ abstract class DataExtension extends Extension {
 		'api_access' => false,
 	);
 
-	static function add_to_class($class, $extensionClass, $args = null) {
-		if(method_exists($class, 'extraDBFields')) {
+	static function get_extra_config($class, $extension, $args) {
+		if(method_exists($extension, 'extraDBFields')) {
 			$extraStaticsMethod = 'extraDBFields';
 		} else {
 			$extraStaticsMethod = 'extraStatics';
 		}
 
-		$statics = Injector::inst()->get($extensionClass, true, $args)->$extraStaticsMethod($class, $extensionClass);
+		$statics = Injector::inst()->get($extension, true, $args)->$extraStaticsMethod();
 
 		if ($statics) {
-			Deprecation::notice('3.1.0', "$extraStaticsMethod deprecated. Just define statics on your extension, or use add_to_class", Deprecation::SCOPE_GLOBAL);
-
-			// TODO: This currently makes extraStatics the MOST IMPORTANT config layer, not the least
-			foreach (self::$extendable_statics as $key => $merge) {
-				if (isset($statics[$key])) {
-					if (!$merge) Config::inst()->remove($class, $key);
-					Config::inst()->update($class, $key, $statics[$key]);
-				}
-			}
-
-			// TODO - remove this
-			DataObject::$cache_has_own_table[$class]       = null;
-			DataObject::$cache_has_own_table_field[$class] = null;
+			Deprecation::notice('3.1.0', "$extraStaticsMethod deprecated. Just define statics on your extension, or use get_extra_config", Deprecation::SCOPE_GLOBAL);
+			return $statics;
 		}
-
-		parent::add_to_class($class, $extensionClass, $args);
 	}
-	
+
 	public static function unload_extra_statics($class, $extension) {
 		throw new Exception('unload_extra_statics gone');
 	}
diff --git a/model/Hierarchy.php b/model/Hierarchy.php
index d6100fa29..3bcc25a20 100644
--- a/model/Hierarchy.php
+++ b/model/Hierarchy.php
@@ -25,9 +25,10 @@ class Hierarchy extends DataExtension {
 	function augmentWrite(&$manipulation) {
 	}
 
-	static function add_to_class($class, $extensionClass, $args = null) {
-		Config::inst()->update($class, 'has_one', array('Parent' => $class));
-		parent::add_to_class($class, $extensionClass, $args);
+	static function get_extra_config($class, $extension, $args) {
+		return array(
+			'has_one' => array('Parent' => $class)
+		);
 	}
 
 	/**
diff --git a/model/Versioned.php b/model/Versioned.php
index 67dedb5bd..01e583ad5 100644
--- a/model/Versioned.php
+++ b/model/Versioned.php
@@ -107,9 +107,10 @@ class Versioned extends DataExtension {
 		'Version' => 'Int'
 	);
 
-	static function add_to_class($class, $extensionClass, $args = null) {
-		Config::inst()->update($class, 'has_many', array('Versions' => $class));
-		parent::add_to_class($class, $extensionClass, $args);
+	static function get_extra_config($class, $extension, $args) {
+		array(
+			'has_many' => array('Versions' => $class)
+		);
 	}
 	
 	/**
diff --git a/search/FulltextSearchable.php b/search/FulltextSearchable.php
index 77f660fb1..006ac028b 100644
--- a/search/FulltextSearchable.php
+++ b/search/FulltextSearchable.php
@@ -75,14 +75,16 @@ class FulltextSearchable extends DataExtension {
 		parent::__construct();
 	}
 
-	static function add_to_class($class, $extensionClass, $args = null) {
-		Config::inst()->update($class, 'indexes', array('SearchFields' => array(
-			'type' => 'fulltext',
-			'name' => 'SearchFields',
-			'value' => $args[0]
-		)));
-
-		parent::add_to_class($class, $extensionClass, $args);
+	static function get_extra_config($class, $extensionClass, $args) {
+		return array(
+			'indexes' => array(
+				'SearchFields' => array(
+					'type' => 'fulltext',
+					'name' => 'SearchFields',
+					'value' => $args[0]
+				)
+			)
+		);
 	}
 
 	/**