"The ones I asked said they had never heard of that clause being used and that they regularly have claims higher than that."
Any agent who says an insurer will pay beyond the policy limits, is probably a liar who needs to have their brokerage license revoked. Those limits are the way most "cheap" policies are structured to guarantee a profit for the insurer. Policies without the cheap limits are usually sky high--for that reason.
IMIS is a good place to start. Most, if not all, conventional insurance policies in the US will run sky high ($1000/month) if you want coverage outside of the local geographic area without huge deductibles. Get sick or injured on vacation, and you'll pay through the teeth unless you come home before you get treated.