Harbaugh is very unique. Can you name a former all-pro QB coming to coach an NFL team? At least in respect to the modern game. Its almost uncharted, but his coaching ability I dont think is questionable at this time. He comes from a family of coaches.
The rest were good points too, but in ANY sport you name me an elite level player (and that was one thing about Harbaugh, before he went to Indy I was calling him "Jim Horrible" and rightly so..... I never saw a QB go as low as he did and rise so high....it does add to the exception factor because he unlike other top-level guys, the other guys don't understand the extra hard work and not having that extra level to achieve to and it's why they end up being bad coaches)...hell look at Singletary as an example
(or even Del Rio who was an awesome MLB but an average coach)
I'm trying to think of anyone else....it's not coming to me now, I'm sure I missed someone