They have stepping stones to an NFL gig already; they're head coaches with BCS teams. They're not going to step down as head coaches from BCS programs--especially a perennial top-25 program like Pelini has--to be coordinators in the NFL. Pelini makes more money* and has more autonomy, and Patterson probably makes more money and definitely has more autonomy, than coordinators do. And they get to recruit their own players, which not even an NFL head coach gets to do. Forget it. It's complete insanity to think otherwise.
*Pelini makes about $3M per year, averaged, until 2015. http://dataomaha.com/panorama/Bo-Pelinis-revised-contract And you think he's going to be a DC here?