A person on Google groups posted about looking for business insurance for his welding business. He had a hard time finding this insurance.
Here are some ideas for people looking for hard to find insurance, such as small business, or boat, or insurance for race cars. Find a good indepdent agent and ask them to help you. You will probably end up with either a small insurance company, which is fine if it is rated well by AM Best, or a Lloyds of London policy, which is fine as well.
Insurance companies do not write insurance for every situation. There need to be enough people needing insurance for them to consider it. However, Lloyds of London will write insurance for odd things that other people may not. A good broker can help you find this type of policy, if you need it.