I just had this crazy idea for a stage. I know it is highly unlikely but I was just thinking about how cool it would be to have a stage where we fight on a plane. No, no, not Arwings or anything like that. I mean a regular plane from the 1920's, what's it they are called? Oh, yes, a biplane!
Anyway, this biplane is the main stage and it is pretty much made up of one long and flat platform on the top and two short but flat platforms under. The biplane's body would serve as an impassible wall between the two short platforms.
After a while, the biplane starts to move out from the screen in one side as another biplane appears from the other side. The characters must then jump on to the other biplane. Throughout the match, we jump back and forth between the two biplanes. Both biplanes can be perfectly horizontal but sometimes they tilt back and forth... so some items might roll off them and it might be a bit difficult to walk on them.
The biplane is flying around a huge Medieval castle surrounded by green hills and it is overrun with gorillas who are throwing balls at the biplanes. Inside and outside the castle, you can see playing card soldiers/frogs/rabbits, jesters, kings, and queens jumping up and down. The name of the stage would be called "Wonder Kingdom" because it is the setting of an obscure Nintendo arcade game from 1981, Sky Skipper.