In reply to djwilse:
Sportscover Direct
https://www.sportscoverdirect.com/ do it. And cheaper than the usual suspects. I use them - well, that is to say I have paid them to insure me. They are very efficient and pleasant on the phone when taking your money. Fortunately for me I have so far had no reason to claim so cannot vouch for their efficiency at that end of the deal.
Although not specifically mountaineering oriented they and their literature do, for the most part, seem to understand the various types of climbing/mountaineering they might encounter, except for the perennial assumption that "free climbing" means unroped soloing, on which I've tried to put them right.