I think the way this plays out is the B10 goes to 15, then asks ND one last time. If ND says no or asks for too many special concessions that would piss off the other B10 teams, then the conference fills that slot with someone else. They won't have any trouble attracting teams, the money is just too good to pass up. Between their rapidly increasing TV money and the CIC research money it means over ten years an additional half a billion to a billion dollars to a school.
Then where is ND? The independents are likely to get squeezed out in scheduling and BCS/NC opportunities, and if the superconferences then flex their muscles the BCS may die and the superconferences could set up their own playoff, they'd have the juice to do it.
I see a lot of people saying ND should decline the B10, any other conference would be happy to take them in. Really? Any other good choices? The Pac 10 will be full. The B12 will be defunct. The SEC with their horrible academics? The new Mountain West? Whatever gets cobbled together from the leftovers of the BE and the ACC? The WAC or the MAC? Seriously, once the B10 ship has sailed, what is left for ND?
Seems to me the best choice of what is left would be the Mountain West. They already have their own TV network, not making big bucks yet but that could change after everything settles out. With the addition of Boise State if you look at the three pronged litmus test for being an automatic BCS conference they already are better than the BE in at least two of the three requirements. And they are likely to pick over the carcass of the B12 and take in Kansas, Kansas State, maybe Iowa State. It would end up a fair football conference, a pretty good basketball conference. Transportation might be an insurmountable issue, especially for all the minor sports.
But the B10 is the good fit. The benefits of independence have eroded. It used to mean top TV money, now the worst team in the B10 gets twice as much as ND, the worst team in the SEC gets 50% more, etc. Scheduling will become an issue as well. Superconference members will have to pick up a couple more conference games, and they'll want their two OOC games to be cakewalks. An independent ND can kiss goodbye to any NC aspirations once this thing gets established, their schedule won't be strong enough to get consideration, particularly given the influence the superconferences will have.
YMMV, contents may have settled during shipping, etc.