>Sure there are, but not nearly to the extent that exists between European NATIONS. Plus the U.S. has existed as a common entity for 230 years. It isn't a new proposal.

230 years ago Belgium,Italy,Germany and a bunch of others didn't even exist as nations.
One should be better off talking about regions which btw don't stop at some artificial border.
So yes the EU is a melting pot and all the better for it imo.