public function getNestedController() {
      $request = $this->request;
      if(!$URLSegment = $request->param('URLSegment')) {
         throw new Exception('ModelAsController->getNestedController(): was not passed a URLSegment value.');
      }
      
      // Find page by link, regardless of current locale settings
      if(class_exists('Translatable')) Translatable::disable_locale_filter();
      $listing = DataObject::get_one('Listing', "MLS = '$URLSegment'");
      if($listing){
         $URLSegment = $listing->URLSegment;
      }
      $sitetree = DataObject::get_one(
         'SiteTree',
         sprintf(
            '"URLSegment" = \'%s\' %s',
            Convert::raw2sql(rawurlencode($URLSegment)),
            (SiteTree::nested_urls() ? 'AND "ParentID" = 0' : null)
         )
      );
      if(class_exists('Translatable')) Translatable::enable_locale_filter();
      
      if(!$sitetree) {
         // If a root page has been renamed, redirect to the new location.
         // See ContentController->handleRequest() for similiar logic.
         $redirect = self::find_old_page($URLSegment);
         if($redirect) {
            $params = $request->getVars();
            if(isset($params['url'])) unset($params['url']);
            $this->response = new SS_HTTPResponse();
            $this->response->redirect(
               Controller::join_links(
                  $redirect->Link(
                     Controller::join_links(
                        $request->param('Action'),
                        $request->param('ID'),
                        $request->param('OtherID')
                     )
                  ),
                  // Needs to be in separate join links to avoid urlencoding
                  ($params) ? '?' . http_build_query($params) : null
               ),
               301
            );
            
            return $this->response;
         }
         
         if($response = ErrorPage::response_for(404)) {
            return $response;
         } else {
            $this->httpError(404, 'The requested page could not be found.');
         }
      }
      
      // Enforce current locale setting to the loaded SiteTree object
      if(class_exists('Translatable') && $sitetree->Locale) Translatable::set_current_locale($sitetree->Locale);
      
      if(isset($_REQUEST['debug'])) {
         Debug::message("Using record #$sitetree->ID of type $sitetree->class with link {$sitetree->Link()}");
      }
      
      return self::controller_for($sitetree, $this->request->param('Action'));
   }