What sales level is needed for PS3 devs?

[Entroper]

NJ5 said:

Interesting. Even more interesting questions are:

- what level of PS3 sales is required for exclusives to be financially workable? How many PS3 exclusive games have made a profit?
- in multi-plat games, what is required for most devs to give a damn about the PS3 versions, instead of launching defective software with framerate drops and other problems? 

Indeed, the one thing missing in the OP is the budget required to do more than a half-assed port.  10-15% gets you bugs, framerate issues, etc.  How much did the developers spend who wrote two versions of the game from the ground up?