Here is where I shall post updates to my County-BAM, so they do not flood the Map Thread.
Good job on the map. once the whole U.S. is done we could use it for election mapping. Others ideas for the map would be evolution of U.S. counties overtime and congressional districts.
That's a very good county map. Are you intending just to focus on this part of the US or eventually extend it to the whole country (though that would certainly be an Uber-BAM).