[Overflow]

OMG.

Just look at these videos first of all if you aren't familiar with either game (is there any such person?)
Playstation All-Stars Battle Royale
Smash Bros. Brawl (it was harder than it should have been to find footage of a normal match)

Those two styles of gameplay are so similar. Some call rip-off (which it is) but that's besides the point. Everything I've heard about the Playstation game is that it controls and feels much like Smash Bros., although how you win is a little different. But the gameplay is so similar that a crossover fighter would be SOOOO easy to do, and incredibly AWESOME.

You would build damage and could die by being thrown off stage like in Smash Bros, but while battling you'd build up your meters which you could use to unleash devastating Final-Smash-like attacks like in Battle Royale.
Mario Vs. Sackboy, Link Vs. Kratos, Samus Vs. Colonel Radec, Ness Vs. the Gran Turismo Car, the possibilities are endless! And not only would it be a blast to play and be a very (conceptually, anyways) easy fighter to crossover, it would sell MILLIONS. Of course, they would need to include cross-platform online multiplayer and trust me, the world would go wild.

And what a great show of company camaraderie, am I right? For Nintendo and Sony to collaborate on such a project would be outstanding. I know Nintendo's sworn to never have a Nintendo character on a non-Nintendo platform, but they should really make an exception for this. If they could get Microsoft in on it too then it would be the greatest crossover in gaming history.