Like Onslaught and WaterWarfare (wiiware online FPS).
Perhaps you'd like an appetiser before C2?
There's a cool looking Hastings paintball 2 coming out for Wii in autumn/fall.
Apparently it features 20 online. Alas I would have said Transformers WFC is looking a fine online shooter too... ..For HD machines. Wii version doesn't have WiFi! A shame, it could have been good. --- Nintendo translates as Leave luck to Heaven.