The author seems to be unsure as to how widely the 2500UX was sold; I can confirm first hand that it was a real thing; I obtained parts of one from a dumpster dive at a Canadian university in the early 2000s. Sadly the case was mangled by a friend who really wanted its floppy drive for an SGI Indy we'd found in an earlier haul...

(I still have the 2500's accelerator card. The Indy is intact, boots, and sitting dormant in a cozy heated garage on a farm somewhere. There's also this hilarious story about how I tracked down the machine's original owner and naïvely asked him for help with removing the root password. He was amused and actually did so, though not without throwing a fair amount of shade at the university for poor hardware disposal practices...)