Man if it was 4 player i.e. Gauntlet, then it will be damn awesome and should be it's own game.
This made me thought of another thing, how ****ing awesome would it be if there was a Gauntlet mod/conversion for Left 4 Dead. If some smart people can modify the A.I Director to constantly spawn monsters everytime, the game engine could be perfect for an FPS Gauntlet game.