I'm sorry I don't have any good info for you Andy, but I am so curious.....what's a "mini-craft drill"? Is that what we call over here a Dremel tool? And are you sure it doesn't just need a new set of bearings? Or brushes? I've brought back many a hand held grinder and a couple of hand held drills that way.
The next deeper repair would be to rewind the armature and at that point I usually decide I've passed some kind of balance between amount of time invested to return on said investment. I do get really attached to my tools I've had for a long time. I have all of my first Proto mechanic starter set from 1975, except the top box and a couple of pieces. They truly don't make them like that anymore and it might be true with your drill, dunno.