I think you're somewhat misunderstanding the role that CUDA plays in all of this. You wouldn't need Quadros because the CUDA cards would only need to be respons

I think you're somewhat misunderstanding the role that CUDA plays in all of this. You wouldn't need Quadros because the CUDA cards would only need to be responsible for performing the raytracing calculations, not actually rendering the image (unless you want it to). So they could have had 4xGTX295's, equivalent to 8 of the boards used in that presentation, just crunching numbers and then one workstation-class card to render textures, etc if they were concerned about render quality. If someone was still concerned about using GeForce cards, Tesla C1060's still cost only about $1K a board IIRC, and I think they'd be way faster at this sort of thing than the GTX285 used.