I know this is an older post but if you're still looking try your local insurance agent. They have the resources to locate an underwriter that can issue a policy for your location. Just make sure you explain to them exactly what you will be doing so you have the correct class code on your policy.
The best option is to find an Independent Insurance Broker or agency that will seek out a variety of insurance options for you. A broker will become your intermediary and do the legwork for you. They will locate several options, and tell you the advantages/disadvantages of each.