As sample2501 said: it works with mods, but at least on the old xbox with some problems.
Honestly, I've got an old heavily modified xbox with integrated USB hub and a Quake 3 port. The game is running on top of a very small linux environment - that costs some performance, because it's not native for the xbox OS.
Anyway, you can play the game with keyboard and mouse, but also completely with your joypad - together with normal PC gamers. Unfortunately you don't even reach 76 frames and the game is lagging when someone is connecting to the server.