It has been tried. It was attempted. But all other incarnations of a hand held fighting game, let alone Street Fighter, were totally lame. Does anybody remember Killer Instinct on the Game Boy? Regardless, what Capcom has done is make of the most deep fighting games, and the absolute winner of handheld prize! What we get is a bunch of characters (26: 13 from Capcom, 13 from SNK) from all sorts of different games. I was trying to pin all the references, and while I think I know most of them, I am sure I am missing some. There's Art of Fighting in there, and some Samurai Shodown, Fatal Fury, and Dark Stalkers. But of course, let's face it, it is a Street Fighter game -- with the most guys in the game from Street Fighter (10 of the 13 on Capcom's side), and as a huge Street Fighter fan, I was not disappointed.
There are loads of options, too. You can play three distinct ways, one on one (ala Street Fighter II'), two on two (ala Marvel Vs. Capcom), and three on three (ala King of Fighters). All three are unique and have their advantages and disadvantages. Plus there are the Olympics that let you test your refelxes in a bunch of mini games. A few stand out, but more importantly, it's the way you gain more moves for your character.
Without a question this is the game to own (even if you don't like fighting games) for the Neo Geo Pocket Color. There is so much here you just cannot get bored. I cannot think of a game more deserving of a perfect rating