Yeah, it's late but don't diss the Virtual Boy! That thing would have been the shit if they had developed more for it.
Anyways...
I don't think that emulating the xbox would mean MS Games' death. It may actually breathe life into them because some of the games that the xbox has aren't that bad. And if they're emulated, then that's that many more system that MS can target for their games. And if I remember correctly, they make most of their money from the games.
Lazygamer:
The gamecube may not be emulated anytime too soon except for people who own Macs, since it's a PPC based system. Even then, you'll have to get past the copy-protection.