Some one lese here actually thought of that idea long ago (I think...). It would be an AMAZING idea regardless of who thought of it!
Game Boy Advance is capable of displying full 3D polygonal images, even if they are of a very limited amount... Some driving games for the GBA (the GT Advance series, most notably) feature fully polygonal cars and environments, though the textures in many of these games are terrible (worse than on PlayStation 1!)
I read that a graphics technology company created a new 3D graphics engine for the Game Boy Advance that would be used in the next Crazy Taxi game, so maybe Nintendo would use this graphics technology for a portable Smash Bros. game (if they ever make one...).
I wonder how Nintendo would be able to create the complex character models in Smash Bros. using the GBA's limited polygon features...
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People who like video games should also like Nintendo. People who don''t like Nintendo obviously don''t like video games.