You might not be aware but medical tourism is already well established and growing.
Several Central American countries have already established close relationships with established American medical institutions and have built hospitals. Also, you don't have to pay cash. International health insurance is offered by several companies.
One recommendation I would offer is drop your insurance in the USA, buy an international plan, establish a relationship with a Doctor who has admitting privileges at a hospital you like and in the event something bad happens and you can't leave the USA buy insurance from an exchange on the way to a hospital. I doubt most people will do this, but some will and 15 years from now we will read stories about how "unfair" it is that they have better healthcare.
Never thought about an international plan. Do you have any good links to such plans?