We can't wait to see the code you're going to contribute to do this. ;)
I wouldn't spend effort on waiting if I were you; I'm thinking in terms of Mailman 3.
I'm trying to modularize the web code now; I'm using something vaguely like a pipeline. At the very least, all of the code that applies to sequences should work for lists of users/lists/messages.
If you want to play along, check out the soc2006-webui branch :)