This is a hypothetical idea I had, which is very naive and not very practical. If you wrote drivers for an ez80 processor with the usb port, could you send shader code and run it? I'm just curious if anyone else had this idea. Thinking about the hardware limitations, I know that the data transfer speed is abysmal, and there isn't enough power (which could be solved through external power). If anyone knows anything, I'd love to hear suggestions.

Most GPUs operated using DMA, so it's not really practical over USB.

It sounds like a neat idea, but I agree with Mateo on this one: the limitations of communicating over USB aren't practical; maybe offloading some operations to the computer over serial may sound cooler. But there's no harm in trying both.

Regarding graphics hardware assistance perhaps over USB might be a bit impractical but interfacing with an external device only to stream the results back ala Calc2Key might be possible (albeit lag).

Another option would be a hardware mod to perhaps link in with some kind of graphics chip over spinor something, or perhaps a community hardware redesign project.

None of these are particularly trivial however.