It sounds awesome, but to avoid sue city, just use some tactful yet obviously linked renaming. That and simplify - you only really need two factions. Microsoft and Open Source. The others can come into special powers, mwhahahaaaa.
I'll email Microsoft's PR department, and in the email I'll put "If you do not reply within 3-4 business days, I will assume that you agree to the following terms:
a) Allow for the derrogatory use of Microsoft's brandnames and trademarks
b) Allow for the truth of Microsoft's shittyness to go out
c) You get the point...
this mod is possibly the dumbest idea i have ever heard. sure it's an "out there" idea but who the hell is going to waste their time playing it? i only waste time playing rts games where you can either hack off someones limbs or blow the shit out of them.