You might be able to go to Chubb directly (but it is more difficult), or you could contact your personal insurance agent for possible coverage.
PPA membership is a good bit more expensive, and they have coverage similar to the NANPA arrangement through Chubb/Rand.
I have used the free PPA coverage and it has a deductible that exceeded cost of repair for a dropped lens. I use the NANPA coverage now. My wife's gear is on our personal homeowners rider through Cincinnati.
I would expect to pay $400 per year for $20,000 in gear on a professional use policy. You might choose to self insure filters and misc. items to keep cost down. Realistically, it's claims for $500 or more where you really want coverage.