My inital idea is to beam-form 4 1080p micro screens per eye to look like a single 2160p image.

Yes. I know. That's over £880 in screens alone. At that kind of cost, I certainly want to be looking around to see if if I can get an >60Hz refresh solution.

I also wonder if it's possible to first split the beams in half to cut the amount of needed screens down to 4. It would mean that each eye only gets an identical image though.