I am surprised that with Nintendo's tendency of turning every single franchise into a portable game they have yet to make a SSB type game on the GBA or DS.
I'm sure the main complaint is that they can't get the engine to run properly in handheld form. The creators of Jump superstars did a good job of creating a SSB like fighting game. In fact, I would love to see its character assist engine used on a SSB game. The manga panel system looked complicated, but unique and deep. Think of it as Brawl's sticker power ups, but with a permanent effect on the characters.