Some notes so far. The motherboard and processor are identical to the standard TypeX2s, but the video card is a RADEON X1300LE. The I/O controller board is much bigger, and plugs into the PCI slot as well as Serial. It's labeled BACK UP P.C.B. The PSU is different of course, as well as the shape of the case; it's smaller and has fans in different places. The Taito Type X2 logo is stamped on the front, not the top.
The board itself gave POST beeps that I haven't bothered to decipher yet, so I ported stuff to a different X2 to test. It didn't come with a dongle and sure enough gave a 901 error. I don't remember if that can be an indicator of BIOS-based security, or if it was for sure just a dongle key. I however did unpack the game, trying to boot through a loader it gives me a SERIAL OPEN ERROR, saying that a file was not found. The game.exe is labeled as "TYPE-X GAME CREATED BY MOSS." It only has two tracks with both the short and full version of the theme, and maybe 4 or 5 sound effects.
Just thought some of you here would be interested in the findings, since I've never seen this kind of deviation in my years of working with this hardware. The PCB is sufficiently filled with JP arcade dirt to know it had use in public. If anyone can shed some light on this, it'd be great! If not, I'm going to do more research with it and I'll report my findings. Hope it's of interest to someone!
Some comparison shots:
Detail on PCB differences:
