I had a bunch of people around the house yesterday, and we were playing Dead or Alive 3 tag team so that 4 of us could play at once. I got thinking though, and what would be really cool is if there was a game that allowed 4 characters on screen at once, all fighting each other (kind of like a royal rumble in the WWF)

Anyone know of a fighting game like that for the Xbox?

Not for xbox as far as i know but they do exist. Power Stone 2 for dreamcast is a good one, and the gamecube has Super Smash Brothers.

For Xbox, Kung Fu Chaos has this feature. The replay is pretty damn cool as well.

For the cube (and soon on the XBox) is Godzilla Destroy All Monsters Melee.

Wu Tang Clan and Thrill Kill on the PSX....

Super Smash Bros Melee or whatever it is called both on N64 and Gamecube...

Kung Fu Chaos on Xbox

Deathrow is more of a sports game, but you can have 4 players and the fighting is actually pretty damn fun, especially versus your friends

I know it's not really a fighting game....but sorta...

Hunter

Marvel vs. Capcom (Dreamcast)

Onimusha Buraiden for PS2 (not yet released)
http://www.gameforms.com/games/ps2/onibur/media/media1/

Some westling games are.

Super Smash Brothers for N64, YOUR BEST CHOICE

I don't have any friends but I'm so there

Four players, not four charactors.

can you get an emulator and play Saturday Night Slammasters?

Powerstone 2 rocks.