Unfortunately, none of the State farm agents in Houston agreed to a stand-alone policy. I think it differs by location and the agent involved.
Do you have a homeowners/renters policy with them? I'm pretty sure that's the only way they'll write a Personal Articles policy. It's the same policy that covers jewelry, fine art, etc., above the basic limits on the primary policy, so if you have home/rental coverage with them, and the agent still won't write a PA policy, I'd get a new agent or call State Farm directly.
You are right, they will write a personal articles policy WITH a renter's/homeowners policy. However, they didn't agree to a stand-alone PA policy as miah mentioned in his post. I have heard State Farm agents do so elsewhere, but not in Houston.
I don't need a renter's since I live in a high-security apartment for doctors and scientists with police surveillance and close-circuit cameras, so I am trying to get an insurance just for the photography equipment against accidental damage and security away from home, as is available in the UK (for non-professionals). I guess I might end up getting a renter's after all, but I would like to see if there are any options.
Theft is not the only reason to have renter's insurance. What if the place burns down, gas line explosion, water pipe breaks and floods your living area.......... All the security won't stop things like that from destroying your property. Renter's insurance is cheap, you need to get a policy.