Well, the score is propane torch 1, broken bolt 0.
I did what Boatdood was suggesting, heat it and beat it. My particular bolt was the one in the midsection, right above the trim tab. I was pulling the lower unit and this bolt snapped on me instantly, no warning, barely even got the socket on it. It only snapped the head off, so once the lower unit was removed it had plently of shaft length to get ahold of with some vice grips. I used a propane torch, kept steady heat on it, and every minute or so I'd give it a few good thumps with the vice grips, either side to side or just directly on the bottom of the bolt (where the head used to be before it snapped). Did that for about 5 mins, locked the vice grips on, and although it was a bit stiff, it did come out without needing anything more than the vice grips. I had a 2' steel bar for a breaker bar if I needed it, but I didn't.
Just wanted to pass on the info in case others are keeping an eye on this thread also.
And thanks to those who replied to the original posters' problem, it helped me.