Though I cannot for the life of me remember where an elected president was knocked off in a nail-biter. I'm pretty sure that the map will either look like this or that unless we really have become a country that divided.
or
Romney will win by the same margin McCain lost by doing OK amongst Indies in places like Ohio but really good amongst "Obama Republicans" in places like Colorado, Oregon and even Connecticut.
I just have this feeling that if it goes to Romney, it goes to him through some black swan even in October where he wins big.