Ray tracing is an amazingly compute intensive operation. Producing a high quality image can take hours even on well specced machines.
It can be done in real time but only at very low resolutions, not nearly good enough for games.
I was thinking up the second version of the PS4 proposal when I thought up a way of accelerating raytracing in software. I've now written the basis of this down in a (long) document and posted it, it is called Directed Rendering
It is a technique which should make ray traversal a lot more Cell friendly.
It works by breaking up the problem into low resolution and high resolution phases and organising the processing and assigning it to SPEs. This removes the randomness from the problem making the data required for high resolution phase and texturing predictable and thus easier to fetch. This should be very Cell friendly.
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