This one-piece case design has worked pretty well:

Print quality on the lettering isn't the best, but I've gotten my printer better dialed in since then.  Most of the case gets printed, then the job pauses so you can drop in the board.  Printing continues to then enclose the board in the case, leaving only the USB plug at the end exposed.  If the bit of plastic under the plug separates (as mine did), you can reattach it with some double-sided tape or superglue.

We have new people here since the last update, so I might prep a couple of devices for them.  Beyond that, perhaps the remaining boards (I had 10 made, and have used 4 so far) might pop up on Tindie.