As the OP I would like to thank you for your replies and also clarify a few things:
1. Both the guy who hit me and myself were well aware of the hazards of thrown up gravel on twisty roads (at any time of year) and the hazard of left over winter sand. We had both ridden about 50 miles of pristinely clean road in opposite directions before he encountered sand in THE ONLY passing lane on this whole highway. So I can forgive him for not even LOOKING for sand in that passing lane - I wouldn't have.
2. We both had a lot of time to look and talk before help in the shape of a cop and a tow truck arrived. Let me assure you that thin coating of sand was very hard to see when we were standing there.
3. The guy who hit me was passing a few motorhomes at a reasonable (except for that sand) rate of speed. Had our positions been reversed, I'm pretty sure I would have closed the throttle when my back tire swung out and lowsided. This guy was a good experienced rider who did everything he could to regain control.
4. I don't think "target fixation" by either of us caused the crash. I aimed to the right and braked hard. He tried to get the bike under control and then braked hard when he got shot into my lane when his back tire hooked up.
5. Perhaps of interest - maybe a half hour after the crash I wondered "did my head hit the pavement?" Sure enough, there was a nice gough in my Schuberth. The helmet saved me from a bad headache if not something much worse.
6. I'm a little surprised that none of you seem to place the blame on the road crew or whoever employed them. If any of you have the computer skills I lack to determine whether there were other accidents at this passing lane of the Bear Tooth Pass road in July 2008, your research posted here would be most welcome.
7. In retrospect, ANYTHING except slightly harder braking (real head on collision) would have been better, in fact made this a "close call." Don't think I can agree with general advice not to brake hard when faced with an unpredictable situation though.
I welcome other opinions. Hopefully we learn through this forum to think through our options before they are there in real life. Well, actually I think we just react and think about it later. But it is entertaining reading and writing on cold winter nights.