Obviously this is just speculation, and there's a lot of Ifs... but if like many people have assumed you can use both the classic controller and the game cube controller it should be possible to have an eight player game. Bomber Man '93 from the virtual console kinda supports this as you can have a 5 player game.
So I'm just throwing this idea out there and I want to know:
1.) If you think it's a cool idea or if more than 4 players is just stupid
2.) If you think they'll have more than four players
Myself, I hope they have an 8 way brawl, cos that's what brawlin' is all about; lots of people and chaos. All I know is I'm gonna get me some more friends just in case