Yes, there are rumors of a Smash Bros. DS, but none have been confirmed. The gameplay would have to be seriously tweaked to incorporate the touch screen and a touch-screen fighting game sounds wierd to me, but I'm always open to new ideas. What scares me more, though, the the Revolution version, due to the rumored wierd controller. A fighting game you control by twisting a giant analog stick and attaching it to a touch-screen/latch in order to pull a twisting screw out of a rubber pully device just to make your fighter kick is not something that would appeal to me at all.
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"We get signal. Somebody set up us the bomb!" "What you say!" "All your base are belong to us!"
-Last Alert (PS1)