UNC and UVa have to be at the very top of any Big 10 expansion list. Fantastic state schools in fast growing border states with large media markets. UNC has one of the best basketball programs in the country, and UVa has...great academics and is in a big state.
I have to think that if UNC and UVa called, the Big 10 would answer. Maryland is a little less clear, because their finances are so messy. I think the SEC would take VTech in a heartbeat. They probably would want a North Carolina school, which leaves them with NC State. The SEC didn't add Missouri and Texas A&M with the plan of stopping there. I think they want two eastern schools in a state they are not already in.
Rumors are teams are already trying to abandon ship from the ACC. If the Big 12 only takes two schools, can the ACC stabilize at 12? Possible, but I would want a Grant of Rights if I was thinking about joining that league after a departure.