These are things that are planned added 'some time in the future'. Please try Mumble out before you comment on any of the ideas below.
If you want to help out with any of the below, great! Be aware that during the alpha/beta stage the code will change quite a lot, and public CVS lags quite a few hours behind developer CVS, so you might want to drop us a line first to let us know you're working on something. That way we can leave those files alone while you work.
We need some more field testing, but we are really feature-complete for what should be in the 1.0 release. So the "To-Do" is actually just to be sufficiently sure 0.9.2 (current CVS) is stable enough, release it and if no bugs are reported make that the 1.0 version.