It's been stated by Sony (or at least one of the head guys working on the PS4). Random link: PS4: Cerny and Ito talk about Backward Compatibility and x86 Architecture - The Gamers DropThe Gamers Drop
Good info. Thank you.
This makes me sad, but I understand the reasoning. It's good that they're dropping the cell processor. I'm not sure if I'll be an early adopter, but I'll still get one. Depends on finishing out some of my existing games.
The main reason I have a PS3 is for the NCAA football franchise and Gran Turismo, so I can probably wait till the next installment of those come out.