I see your point, but is that not just a question of making that tool (software) that can combine USB and PCIe to talk?

I was just thinking if you have windows 10 on a motherboard where you have cuda running, why should it not be possible to run Windows 10 iot on a Pi and then have the same setup.

Then it should just be matter of how to get it to communicate.

Maybe I'm way off here.

Just a thought.