Very, very cool! I've set up a dual-GPU system in the past using two nvidia GPUs and whilst I found the trek towards PCI passthrough to other virtual machines

Very, very cool! I've set up a dual-GPU system in the past using two nvidia GPUs and whilst I found the trek towards PCI passthrough to other virtual machines rewarding when it finally worked, I also found the arrangement to be inconvenient. What you've achieved here, seems the ideal. Well done :) I will either patiently wait for an Arch Linux version of the install, or I'll eventually end up impatient and see if I can rustle up something - an install script is an install script, it should be just a matter (famous last words) of altering the install script/procedures to suit.