If I had no family and no moral responsibilities here, I'd be open to the concept. But I have family (more than just my wife & sons), employees, and - to a much lesser degree - clients, that I'm responsible for. May not be legally responsible for the welfare of our employees or clients, but the fact is I'm not legally responsible for most of my family either; just personally feel that I should do as much as I can, for as long as I can, for them.
I've heard some folks mention south- and central-america. If I were thinking along those lines, it would probably be in those areas; but I really haven't given it much thought as it's not an option I've really looked into.
"The best a man can hope for is a chance to prove that the good lord didn't make a mistake putting him here in the first place." - Will Sonnett