Sugestion: Membership Plugin

Hello to all!

I'm running a WPMU powered website and what I need is a Membership solution, something similar to but modified for WPMU. This movie describes how above mentioned plugin works for WP single installation:

User Blogs/Profiles on my MU site have only one member - Blog Administrator which has limited capabilities. So I'm wondering if Andrew and his team are planing to develop something like this in the future. I think that extended version of 'Upgrades' plugin (which I haven't downloaded) could be a good start.