As a bit of a counterweight, yes, the US is 'sue happy' but being abroad typically takes a good part of the wind out of the 'I'll see you in court' attitude. It takes a lot more from the litigating party to set up a lawsuit with an overseas party, on top of that the courts in the UK are much less likely to award idiotically high damages.
As a first stop, before talking to insurers I think you should talk to a UK based lawyer that has experience defending a UK party from a US party suing them to get a good idea of the lay of the land and the likely hood of such a lawsuit.
As soon as you incorporate in the US your chances of being sued will go up enormously, and so will the cost of your defense. In the UK it will be manageable, in the US it will likely put you out of business. As one friend who runs a consumer electronics company said "The US is a very large market and we can not ignore it. But the cost of doing business there in terms of legal hassle is something that we simply pass on to the consumers in the US, which is our way of dealing with it.".