Apple PowerMac 9500
This is another Craigslist find. It came from a guy who was in the publishing industry (newspaper, I think), so had ended up with a few different models. I had sought out a PowerMac 9500 specifically because it is one of the few PCI Macintoshes, making it capable of running the PPC version of BeOS.
This one came with a Sonnet G3 upgrade installed, which fortunately does not prevent the running of BeOS. I'm not sure it makes getting BeOS working any easier though. The main problem with this system is just how brittle the plastics are. Every single time I open it up, some little bit breaks off, never to be attached again. And even though the case is mostly metal, every edge and in-between is filled or covered in plastic.