I don't see BC either, I would guess UVA and UNC. The Big Ten is all about adding contiguous states, Maryland seems like it's acting as the bridge between Pennsylvania and the big prizes in Virginia and North Carolina.
Question is, when B1G goes to sixteen does the SEC do the same? NC State and Virginia Tech would have to be the favorites, assuming UNC is off the board. VaTech is a no-brainer, and the SEC would have an easy choice to pick a North Carolina school (as they don't have one yet, and in the past they didn't want to add a school in a state that they already have). I would lean towards NC State but you can't ignore Duke's prestige as an academic institution and a basketball institution.
If the Big 12 wanted to join in... Florida State, Clemson, Georgia Tech, Duke or NC State, Louisville, Pittsburgh, maybe even Notre Dame would all be ripe for the plucking to get to sixteen. Just have to hold it together as the Pac-12 may come back to our area to steal Texas/Texas Tech/Oklahoma/Oklahoma State again. If we hold them off, their options are really limited. BYU, San Diego State, Boise State, Fresno State, Colorado State, Nevada... that's about it for them to choose from.
So much speculation, so little time