As I've said elsewhere, I've got a group that gathers a lot and we love playing this. The problem is we don't often have access to more than 2 TVs and systems. 2 and 4 player games are so empty and lacking. I'd love to have a new mode for these smaller groups with maps designed to accomodate them.
How about something like Juice Tag? A random player gets powered up with say... Permanant Bacon effect, no healing and double juice gain, then the other players have to kill him , the player landing the deathblow gets the power up and so on.... When the time ends, the winner is the player with the longest survival time when juiced. Any turrets purchased attack everybody, even the person who paid for them and purchased class bots wander around the maps in circles looking for people to maul.
You could always try the Scramble mode of Blitz, it's final round is always crazy. SUdden Death takes so long before it gets interesting In the new Achille's, Aptilube, and Uncle Tap's arenas!