@ Boing: to the best of my knowledge it goes like this:
The 128D was the second revision of the 128, they changed it to the desktop form-factor and put a 1571 inside the case, which was plastic and had the carry-handle. The plastic case hadn't a snowball in hell's chance of being legal in the US due to the FCC regs (they later exported their crazy regulations to us via the EU IIRC).
Anyway to sell the 128D in the US they repackaged it in a metal case to meet the FCC interference regs and also made some motherboard revisions to reduce costs including integrating the 128D PCB with the 1571's PCB (hence the 'CR' in the name) producing the 128DCR. It also featured the max 64K of video ram and a different VDC.
This new cheaper board couldn't fit inside the wedge case so they prototyped a version called the 128CR which had the mobo revisions to reduce cost and improve the video capabilities but removed the 1571 bits of the board. I have no clue if this version actually made it to production though. Further they made a few mockups of a wedge 128 with a built in floppy, might have been a 1581, not sure. I think Zimmer's site has the pics - some had a deck-loading mechanism, very retro. None of those were actually real though I don't think.