* Allow sub-themes to have their own .tpl.php template files.
  *
  * This is an exact copy of _phptemplate_default() with the addition of the
- * $theme_path and $parent_theme_path
+ * $theme_path, $parent_theme_path and $zen_theme_path
+ *@param $theme_path - path to theme, either sub-theme or sub-subtheme
+ *@param $parent_path - if sub-subtheme, then it will point to subtheme, if subtheme, it will point to zen.
+ *@param $zen_theme_path - either way, this always points back to zen.
  */
 function _zen_default($hook, $variables, $suggestions = array(), $extension = '.tpl.php') {
-  global $theme_engine;
+  global $theme_engine, $theme_key;
 
   if ($theme_path = path_to_subtheme()) {
-    $parent_theme_path = path_to_theme();
+		// The following adds *.tpl.php support for sub-subthemes
+		$parent_theme_path = substr($theme_path, 0, -(strlen($theme_key)+1));
+		// We also need to keep track of where Zen is, so we can load the *.tpl.php files 
+		// if not found in parent path..
+		$zen_theme_path = path_to_theme();
   }
   else {
     $theme_path = path_to_theme();
@@ -82,6 +89,10 @@
         $file = $parent_theme_path .'/'. $suggestion . $extension;
         break;
       }
+      elseif (!empty($zen_theme_path) && file_exists($zen_theme_path .'/'. $suggestion . $extension)) {
+        $file = $zen_theme_path .'/'. $suggestion . $extension;
+        break;
+      }
     }
   }