Working on Rebirth: nope, because there's nothing to work on. Rebirth hasn't been released and Egosoft hasn't given anything out to even start vague planing about.
Working on TC: few members from the old XTM team worked on TC, and some of XTC's model stuff was given to Egosoft for the albion prelude. That's it, though.
Working on 2.0: Some of us are doing just that, obviously - those that have stuff left to do, mostly. If you know what the term "feature creep" means, well, yeah, it has reared it's head once again.