I call a certain amount of BS on the Harbaugh situation in SF. Most of the rumblings I've heard have been perpetuated by michigan people and/or college people. I don't think everything is 100% warm and fuzzy between Harbaugh and the front office, but he still has another year left on his deal. If and when he leaves SF, there will be several NFL teams lined up to pay him 6, 7 million a year.
If, for some reason, Harbaugh doesn't coach next year with the 49ers (or finishes up his contract the following year and doesn't sign an extension), I could see him taking a year or so off to recharge the batteries and patiently wait for the college or pro team of his choosing . The guy has proved he's a great college and professional coach. He'd be the top coaching name in college and pro ranks. It's tough to believe SF will let him walk, and even tougher to believe that if they do, another NFL owner won't offer him basically whatever he wants the following day.
All of this, coupled with his opportunity to take the michigan job previously (and his words and thoughts expressed while it was going on) make the michigan job seem like a demotion-- not even a lateral move. He'd be "settling" for that job, when in reality, he can have virtually any available (and probably some seen as unavailable) job in the entire realm of football.