GS turned down Michigan to remain at Rutgers (he had also spurned Miami). The only thing that took him away from us was the call from an NFL team, coupled with no call inviting RU into the B1G, which occurred 8 months later. Had the B1G called first, GS would have been here to lead us into the B1G and I think the past 7 years would have been very different and infinitely more enjoyable for RU fans.Fickell or Campbell would be good targets for them if they make a change. Bo was an Ohio guy and coached at OSU as an assistant so I don't think that would be stumbling block.
Fickell I think depends if he thinks he'll ever have a shot in the short term (say a few years) that OSU might open up. If not I think he'd go. Campbell I'd be shocked if he wouldn't leave ISU for Michigan. There's a limit to how much he can do at ISU and a Michigan opportunity doesn't come around every day.