If you want to do it without Zend ACL I suggest to write own partial for menu. Then you check current user role (stored maybe in Zend_Registry) with menu item privilege from xml file.
Here you can see how to use custom menu partial https://stackoverflow.com/a/1255289/760866
You read custom xml properties like this:
$properties = new Zend_Config($page->GetCustomProperties());
$privilege = $properties->privilege;
Hope that helps!