I would say the most likely scenario right now is that the ACC tries to expands by just adding Miami. It will be up to the Canes officials to decide then if they prefer guaranteed moneis from the 10 team ACC or if they wish to pursue the new conference that we're talking about. While the latter option is very feasible, it might be too much work to make it really happen, especially in time for BCS and TV contract negotiations. In the ACC, Miami could use out-of-conference games to maintain their northeastern presence for recruiting, plus they'd likely help create the best baseball conference in the country. And as has been mentioned on multiple boards, there'd likely be better traveling among fans from the ACC arrangement then anything that stretches from Miami to Louisville to Boston.
If there were to be a split, however, the timing would be very crucial as well as who signs on from the outset. If the likes of Mimai and FSU commit to a new league early, don't be surprised if the ACC expands to 10 by dropping FSU, GT and Clemson but picks up UConn, Temple, Rutgers and possibly BC. Likely a better b-ball conference, still credible for football plus they retain their BCS status.
After the ACC and the "Catholic" League move for b-ball supremecy, that only leaves eight remaining ACC/BE Fb powers:
The big plus here is that this league is openly advertising for four more members. Louisville and Cincinnatti are givens to me, as CUSA loses some schools to the Catholic league. ND is not in - They'll want to remain indie in FB, join the Catholic league for all else. PSU is a last resort so as not to take away from existing TV and recruiting markets in Pitt and 'Cuse.
Similar stories with UCF, USF and Marshall.
So who's left? Navy and Army will be better off elsewhere. UNCC can't get their FB together in time. That leaves ECU, UAB, MTSU and Memphis as viable candidates(* see below). Pending all-sport compatibility, ECU gets in first. Starts the ACC rivalry off right, better geography and some existing matchups with the new league members. The others seem 50/50 to me.
So, IMO, here's your new Eastern Athletic Conference:
North: Syracuse, Pitt, Louisville, Cincinnatti, West Virginia, Virginia Tech
South: Miami, FSU, Ga. Tech, Clemson, ECU, UAB*
Last twist: Assuming these shifts drive what's perceived as the last configuration of div. I-A schools, I expect some last minute pushing from several I-AA schools that want in. In this case, don't be surprised to hear Ga. Southern bantied about.