My thought is with the possiblity that Miles is going to Michegan and the fact that it doesn't sound like LSU would even look at Pellini. Could TO bring in both Gill and Bo, Gill be HC and Bo be AHC, but basically have Bo here as a HC in training so in a couple of years when he is ready and other teams come knocking he is free to go.
That's my 2 cents because if both Turner and Bo are learning from each other and TO, then the likelyhood of success is that much greater.
This topic has been brought up before, but I'm in too much of a hurry to go digging.