The 11 hours later update...
Last night's post got me thinking, so I took another look at my broken seatback-release lever handle, and I realized it wasn't broken at all. The end of it is hollow (like a tube), and there were no broken edges on it, so I realized that it must have come off its mount. I pulled back the plastic trim piece on the seat that the lever normally mounts through, and saw the little metal arm that it is supposed to attach to. Then end of the arm has a friction clip on it, which holds the plastic lever on. So I just shoved it back on this morning, and it works again! Yay! But the mechanism is rather "sticky" and won't budge unless you get it just right. Pbkid, you should take another look at yours and seee if the same thing happened to you.
Anyone else have the problem with the seatback reclining on its own?