Thanks for the replies, ya'll. I put the key in and turned it back for glow plug (why, I don't know) and it broke off flush. I looked down and saw that I hadn't put the key in all the way and the big shoulder at the head of the key had not engaged. The tiny, keyed part couldn't take the pressure.
Had to grade the driveway, so I got a screwdriver and jumped from battery cable to solenoid hot and it cranked right up. Graded the driveway and went to try and remove broken piece and it had vibrated out somewhere on the driveway. I don't have any electrics hooked up besides the low oil pressure lite and the alternator. So once the starter motor is disengaged, there's no drain on battery. I'll just have to hook up the battery charger from time to time til I get a key. At least I don't have to try to fish the piece out.
I'll call around Monday and see what can find.