@acebmxer Certainly did - and got it working in my Windows guest...somewhat. When that VM initializes, all four monitors are activated by the graphics card, and I can log into the VM via an XOA-connected laptop. Can set up the monitors too. But...can only get mouse/keyboard focus on the main display (which I suspect is due to the way XOA Console handles things). So now I have to figure out a way to pass the keyboard and mouse through to the VMs.
The Linux issue I suspect is due to driver signing requirements but at least this part works. There will be two 4-port video cards in the system - one for each VM that's assigned a pass-through device.