Index: t3lib/class.t3lib_div.php
===================================================================
--- t3lib/class.t3lib_div.php	(revision 4298)
+++ t3lib/class.t3lib_div.php	(working copy)
@@ -4608,6 +4608,8 @@
 	 * @return	object		A reference to the object
 	 */
 	public static function &makeInstance($className)	{
+			// holds references of singletons
+		static $instances = array();
 
 			// Load class file if not found:
 		if (!class_exists($className))	{
@@ -4619,8 +4621,16 @@
 			// Get final classname
 		$className =  t3lib_div::makeInstanceClassName($className);
 
+		if (isset($instances[$className])) {
+			return $instances[$className];
+		}
+		$instance = new $className;
+		if ($instance instanceof t3lib_singleton) {
+			$instances[$className] = $instance;
+		}
+
 			// Return object.
-		return new $className;
+		return $instance;
 	}
 
 	/**
Index: t3lib/interfaces/interface.t3lib_singleton.php
===================================================================
--- t3lib/interfaces/interface.t3lib_singleton.php	(revision 0)
+++ t3lib/interfaces/interface.t3lib_singleton.php	(revision 0)
@@ -0,0 +1,40 @@
+<?php
+/***************************************************************
+*  Copyright notice
+*
+*  (c) 2007-2008 Ingo Renner <ingo@typo3.org>
+*  All rights reserved
+*
+*  This script is part of the TYPO3 project. The TYPO3 project is
+*  free software; you can redistribute it and/or modify
+*  it under the terms of the GNU General Public License as published by
+*  the Free Software Foundation; either version 2 of the License, or
+*  (at your option) any later version.
+*
+*  The GNU General Public License can be found at
+*  http://www.gnu.org/copyleft/gpl.html.
+*  A copy is found in the textfile GPL.txt and important notices to the license
+*  from the author is found in LICENSE.txt distributed with these scripts.
+*
+*
+*  This script is distributed in the hope that it will be useful,
+*  but WITHOUT ANY WARRANTY; without even the implied warranty of
+*  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+*  GNU General Public License for more details.
+*
+*  This copyright notice MUST APPEAR in all copies of the script!
+***************************************************************/
+
+/**
+ * dummy interface for singletons (marker interface pattern) 
+ *
+ * @author	Martin Kutschker <masi@typo3.org>
+ * @package TYPO3
+ * @subpackage t3lib
+ * @see t3lib_div::makeInstance()
+ */
+interface t3lib_singleton {
+	// deliberately empty
+}
+
+?>\ No newline at end of file