You're from the US, aren't you? I'm not too familiar with US insurers, I'm afraid. The company I tend to use are called World Nomads
, and they do cover Americans. They are aimed at budget travellers and so the limits on the personal possessions you can claim for in event of loss or damage are low, although you can insure specific extra high-value items for an additional premium. You get medical and personal liability too as well as cover for a number of sports/activities as standard.
I've claimed with them twice and never had a problem, although they did insist on a doctor's report for the bout of illness I had in Laos before they paid up for it which took a bit of emailing. Despite focusing on the budget backpacker market, they are not the cheapest on the market, but I tend to go with them out of habit and trust. I did a quick quote and a three-month trip comes out at $173 with them.
There's also a company called Travel Guard
who are US-based but I have no direct experience of them, nor have I heard of any reviews from other travellers.
By the way, both of the above links are "affiliate" links - if anyone ends up buying a policy through them, the forum gets a commission, similar to the Agoda setup we have. So thanks in advance if anyone does