The port of Linux on the Xbox is on the way... Soon you'll be able to thank MS for selling Linux-enabled high-end PC at the lowest price ever by making them losing more than USD 195 for every sold item...
What about using the monstrous processors integrated on every decent graphics accelerator for more general parallel computations such as ray-tracing? That's just how the Commodore 64 hackers treat the processing unit of their floppy disk drive...