The at-large bids are all going to hinder on the conference championships, especially considering the PAC-12 and B1G will have their first this year.
The last AT-LARGE bid will most likely be a battle between PAC-12, B1G, and the ACC, since the SEC and Big-12 will most likely have 2 teams in.
Conference championship scenarios are too early to predict, but it will basically boil down to 1)was there an upset and thus a team such as ASU or MSU steals the AT-LARGE bid 2) if no upset, who is the best 1 or 2 loss team.
I don't think VT will be the best 2 loss team, with Stanford and Oregon both looking strong in the PAC-12. It doesn't help that the Cardinal and Ducks are in the same conference and thus only one of them will be in the conference championship.
VT has 2 ways into the BCS: 1) win the ACCCG 2) end the season with 2 losses and watch the epic collapse of OSU, Stanford, Oregon, and Wisconsin each having 3 losses. If VT loses to GT and doesn't play in the ACCCG, VT will probably also need GT, K-state and Nebraska to lose 3 games as well.
It's pretty much Orange Bowl or bust. Clemson has a much better shot at the AT-LARGE, as a 1-loss Clemson is probably only beat by a 1-loss Stanford and 1-loss Wisoconsin.