RE: Insurance idea
Matt-
It is easy enough to get your HO/PUP provider to exclude models. Just ask your agent for a rider and I'm sure they will happily oblige. That would make your AMA coverage primary. It's up to you to decide if you are comfortable with the coverage provided (and the exclusions from coverage), of course. Dunno about obtaining coverage above the limits of the AMA insurance. It wouldn't be a PUP, as they are by nature comprehensive in-excess coverage on top of HO, auto liability, landlord's, etc., coverage. Don't doubt that it could be obtained, but with terms tailored as you would like I expect you might be paying more for admin costs than actual insurance.
AMA insurance for site owners is claimed to be primary, and when it applies the owner's other property insurance is said (in the sales pitch) not to become involved. Frankly, I don't know how that is possible given the subrogation provisions standard in the insurance industry and civil law administered by the states. If you get any info that sheds light on that, please post it for the rest of us.
Abel