Technically if someone had bothered to do an image search on "QSS-2901" per the leads found by snuci/MacJunky on page one it all could have been over right there. (I'm kicking myself for not having done so myself. I actually hit and scanned the same page as snuci when searching that "PC-NRT-5A" model number and didn't grasp what that page was going on about, IE, that the model number was associated with the *original* computer integrated into some sort of dingus, I just saw that the case of their upgrade machine was obviously different from the topic of discussion here. Unfortunately that mislead me into assuming that the model number was a coincidence and that it'd come from some long-dead whitebox puppy mill.) I suppose it wouldn't have necessarily settled the question of whether it was a bottom-up custom job made just for integrating into big heavy things that make loud noises or a slightly-modified off-the-shelf unit, but whatever. When I realized after your next big picture set that not only did this case look generically familiar, I'd owned the *exact same thing* it sort of turned into a mission to put a name to the face.
(Please bear in mind that the next time you find a hunk of junk like this in a thrift store it may indeed be impossible to do that. Unlike the case of Apple's products generic white-box PCs don't have hoards of obsessive fans that document every single aspect of every single model ever sold for future generations to wonder over. )
I dunno, it came off more like "it's this and I won't take no for an answer unless it's proved beyond all metaphysical certainty it wasn't" to me, but I guess it was your favourite.