Most propably Agent, but just sayin it's not impossible they'd turn down a mountain of money to make a game they want to.
New rockstar games franchise exclusive to the PS3
Also, IF five was an exclusive, people would buy consoles to play it. I doubt all of the sales money would go to Sony in a agreement like this. Sony would also most propably overtake XBOX in terms of sales with a move like this, which would guarantee a steady flow of cash for R*
It should also be noted that Take Two turned down EA over a complete planet made of money, just because they prefer to do things way they (or their investors) want to.