I actually sort of regret my timing. After the fact I realized it would have been a lot more fun if I'd waited for you to post your exquisitely detailed photoessay definitively debunking the idea that it could be anything but a custom-fabricated low production run engineering marvel, no chance at all it could just be an (albeit slightly modified?) off-the-shelf item.
Earliest trace of a mention I can find of this case model with casual searching is from late 1998. That doesn't definitively prove that it *didn't* exist in 1996, but...HEH! 1996! The redonkulous fantasy regarding this case's history lives on! [)] ]'>
Remember those links tossed out by MacJunky and snuci on page 1? I think they're dead right. The modifications to that case *completely* fit in with it once being part of a big, expensive high-volume film scanning/photo-processing machine. The labeling matches up, the specs quoted (A fast Pentium III or early Pentium IV) fit in with a 2000-ish vintage case, that chopped-out corner of the case (and the metalwork for the side-venting fan) is the sort of thing a company that makes industrial lab machines could do in house, adding that card-holder thing to counter vibration, it all makes *much* more sense than your "testbench case" idea.
Here:
There it is, what is clearly an Enlight 7101 case embedded in the left side of the machine, a QSS-2901 photo printer. That's what it is/was. So... yes, it is actually "special", this wasn't someone's desktop PC. But it was never a PowerPC prototype either.
(For the record, I figured out what this case was by finding a scanned copy of a July 2000 issue of "Computer Shopper" magazine online. There are pictures of this case *everywhere*, and seeing the bezel totally clinched it for me that I'd had that exact unit.)
EDIT: Here's a picture of a machine with the skins pulled off the left side, there's your case right there, definitively. If you do an image search for the QSS-2901 you'll find another picture of one with the side panel off that shows the computer case inside, with the cover on it, *WITH* the corner notched out for some sort of cable anchor. Just like yours.
