That's the G4/700, lovingly restored, not a speck of dust internally when I opened it last.
Running Mac OS 9.2 and 10.3.5. I managed to acquire a set of Apple Pro Speakers to go with it just a few days ago but forgot to mention them in the thread.It's the same logic board, but without the second CPU board connector soldered in. I suspect there may be some other changes as well, notably lack of supporting hardware for Dual Processors and a slightly slower system bus.
I've seen some impressive PC installations in Power Mac cases. If I ever took that route it would have to be an impressive install, fast hardware and water pump assemblies to cool the lot. Stealth installs are mandatory, the light and fury would have to be visible only when the computer is opened. Tempting, but my priority is still repairing the stock board for now.