[keninsb]

That was pretty scary allright. I had a rear wheel come off on me once, it was pretty funny in hind site. It actually PASSED me on the freeway. No one to blame but myself. I worked at a service station at the time (was about 17 years old) and had put some new (used) tires on. The machine bent the rim and sent the wheel off once I hit the freeway. Thank God no one was hurt.
Anyway, in regards to your problem, good move taking the pics. I agree with the other person that replied to your thread: Bolts may "break off", but typically won't unthread afterward. It would appear that they either didn't tighten the bolts and they worked themselves loose, or forgot to put them on altogether. At any rate, at least SOME of the blame has to fall on the dealership.
I wouldn't hold it against the vehicle. I don't think this is a "common" occurance in any Toyota, and I am SURE we would have heard about it if it were (although I know this may be of little comfort to your wife). I would definitely go for the extended warranty. And one more thing: The piece that they used the heli coils on, is that bolted to the frame or welded on? If it is bolted to the frame I would ask that they replace the entire mechanism. If it is welded on, then replacing would probably cause more problems than help. Just my opinion and I am by no means an expert.
Good luck and keep us posted on the outcome.

Ken