Jeff, I know what you mean about Shasta. I had to go through that same decision process many times for Shasta. What I ended up doing was to shoot a few good shots of the mountain from the trailhead, and then I left the good camera in the car. All I carried up the mountain was a small P&S camera in a padded pouch. It was small enough that I could keep it inside my sleeping bag at night, and I could keep it inside my Goretex shell during the day.
There are so many bad conditions up there that will really screw up a good camera. Cold, wet, ice, volcanic ash dust.
I could be wrong, but I don't think that there are that many photo opportunities high on the mountain that would make it a worthwhile risk for a good camera. For one thing, you are typically walking around with skis or snowshoes or ice axes and you don't have a lot of extra hands for a good camera. For another thing, you have so much overexposed white snow and underexposed dark rock that it is easy to have strange exposures on all shots.