I am considering using the multi level menus plugin in several sites here in Japan. Seems to work well. But I update my sites by SVN and I really prefer to include the plugins as an external reference in SVN so I can update wordpress and the plugins easily when new versions come out.
Why isn’t your plugin hosted on the official wordpress.org SVN repository?
http://plugins.svn.wordpress.org/
Do you have your own public svn server?
Regards,
Ray Mercer