Vanilla 1 is no longer supported or maintained. If you need a copy, you can get it here
I have just tonight started developing an extension which basically adds a member list page to the forum, like on many other forum systems I suppose. It's just sort of a test to see if I can do it really but if anyone wants it then I can release it.
Anyway, it's my first extension so it's not as easy for me as it probably would be for lots of people here but I'm giving it a shot. If someone is already developing one / already made one then let me know and I will stop. I checked the addons db and there doesn't seem to be any there.
As long as everything goes to plan I should be able to release it pretty soon, I'm having a few problems at the minute but I'll give the documentation and the sources another look at and see if that helps.