How about each time you prestige, you unlock a multiplayer "cheat." The cheats would be client-side only, as not to take away seriousness from players who don't have them activated, and would only be cosmetic(audio/visual) so they provide no major advantage or disadvantage. The worst they would do is make enemies easier/harder to distinguish.
Suggestions:
-Paintball Guns
-Paint Grenades
-Replace the skull shown over bodies with a smiley face
-Replace the teams with Government Agent models on one side, Alien models on the other side (same collision mask as normal players, as to not make target easier or harder to hit)
-Hawaiian Mode (floral shirts on players, throw pineapples instead of grenades, etc)
-Cops and Robbers (one team would wear ski masks, the other would wear police uniforms)
-LSD Mode (a color-filter that slowly transitions between colors)
-Different accents for the announcers (Duuuude....enemy chopper incoming, man)
-Slow-Mo/ High-Speed Killcam
-Ragtime warfare(without the sped up gameplay, obviously)
-Whatever else people can think of.
Yeah, I was running out of ideas, but at least some are good (smiley face, paintball, Ragtime Warfare)
As is Nazi Zombies didn't make CoD appeal to stoners enough already :P
I've always liked visual cheats, especially big-head mode (bad idea in CoD, for obvious reasons) so I don't see why it would be such a bad idea in multiplayer. CoD4 had them in single player, WaW had them in co-op, so Black Ops should finally bring them to multiplayer. As they are client-side only, and provide no advantage, the only problem I can see is memory concerns.
