Hmmm... OK, minor snag.  My status LED is lighting up red instead of green, which probably means I wired the LED in wrong.  Probably should've tested it to make sure of which lead was red and which was green before mounting it.  (I used to know which was which just from the shape of the leads and the flat side of the LED housing, but oh well.)  Not a big deal, really, but I'd prefer it to light up green, if for no other reason than that was what color the original C=1541 LED was.  Fortunately, this is not a difficult problem to fix – since the 3-pin connector up at the electronics board isn't polarized or keyed, and the common-cathode wire is on the center pin with the red-anode and green-anode wires on the outside pins, it's a simple enough matter to...

...unplug the 3-pin cable, turn it around and plug it in "backwards"...

...and SHAZAM!, we have a green light!  Sure, it's a kludge, but who cares.   It's a heck of a lot easier than getting that LED back out of the mounting holder to rewire it, especially since it's located in a very inconvenient place and it took me almost ten minutes of microsurgical noodling around just to get it all the way in the holder in the first place!.

Here's a picture of the completed project from the back.  Since all of those connectors are mounted directly on the PC board, and the whole electronics module is pretty tightly packed together on its own little mounting frame, the simplest thing to do was just make a big rectangular cutout and use the original backpanel from the "Combo External Drive" case.  The two round holes above it are where the original Commodore device cables plugged into; it didn't seem worth trying to plug them or cover them up.

And here's the finished project in operation, complete with an IDE drive mounted in the carrier.  This probably won't be its final resting place, but it's good enough for now.  (Eventually, I'll probably get a taller printer stand so both it and the scanner can slide all the way under the printer when they're not being used.)  Note that the case still has the original Commodore 1541 rainbow sticker along the top edge – I think I'll leave it that way.  It amuses me.