I know of one motorsports insurance company that is usually in the rulebook (don't have mine with me right now to check it out). I've talked with them about insurance in the past -- but they insure race vehicles and accessories. I don't know about rider/driver. I can't remember the name - but for years they've had ads in the rulebook.
For personal insurance -- well, ours did cover Nancy's injuries a couple of years ago when she crashed the bike. We paid about $7k out of pocket - way less than the total bill. We did not have anything in the way of special risk insurance - just run of the mill medical coverage. Our ambulance bill was around $11k - we paid $2k, they paid the rest. All in all -- not bad, no rate increase since then.
As for life insurance - well, not long after I started racing our life agent came visiting one day and said "Jon, Northwestern Mutual has asked me to let you know that because of your racing they're going to put a 50% additional rate on your policy because of special risks." Crud -- the bill went up. It turns out that it would have gone far higher if I had just let it go, but I whined and explained that this is a "speed trial", one vehicle at a time, special driver licenses, etc, etc.
The moral of the story - don't worry too much if your medical coverage does not specifically mention/disallow land speed racing. But don't tell your life insurance agent why you head for Bville or EM or any of the events every year.
