Well, I did the ballpoint pen thing that was suggested in the service bulletin posted above, and sure enough, there's an impact point. It's incredibly low on the windshield...below where the wiper blade rests and in the black portion of the window. I have no idea how a rock from the road could have hit that. A rock would actually have had to be coming from above, from the sky, to hit it there. I actually have my suspicion that a tool was dropped on it (I had the oil changed at the dealer on Friday), but there's no way to prove something like that. I guess I just bought a windshield.
'07 Wrangler X Unlimited, black. Just getting started.
*SOLD*'00 TJ Sport, Solar Yellow, sailcloth top, safari/duster combo, 31x10.5 Firestone Destination A/T