As Brian points out, there are some new Orcas specifications available for TFS. I've been working on the Large Group Sync crew for some time, and am very proud of the end result. What used to wind up as a support call can instead be managed by your Team Foundation administrator. While the whole system may not handle an enormous number of users in the system, at least the basics will still work and you can back out to a fully functional state by paring down the number of users. I can't wait until this gets released so you folks "out in the wild" get a chance to see how it works!
Of course, never one to miss an opportunity for some form of celebration, I baked a batch of sugar cookies for the team: