> [...] I've considered buying/tracking down a non functional one and putting a high performance ITX build into it a few times over the years.

I'd buy a classic keyboard case x86 (with PCMCIA card slot, Enhanced Personal Computer Keyboard layout plus integrated trackball), preferably made to last, made out of metal. Sadly, no one makes decent cases for something like a Vortex86. It's either weird mini towers to appeal to the nostalgia of the Old Breed, or cheap 3D-printed contraptions in the vein of stompboxes (for MiSTer implementations). Sad.