http://www.americancollectors.com/
Link above is who I use for my T-16 Universal Carrier and other vintage vehicles that have tyres. They have no issues with the carrier being tracked and having no title since it isn't a street vehicle down here. USAA Insurance is linked to them as well but you don't have to be a USAA member to use them. I've had one claim in the past ten years with my jeep so I know they will pay when needed and don't drop you or jack up your rates just because you used your policy.
Being insured against loss is one thing, but liability is probably more important given the possibility of running something/someone over that gets into your blind spots. Thankfully I haven't had that happen yet.