Nebraska's going to be a rival with OSU and Penn State too. I'd say they'd have a good one with Wisconsin and Minnesota as well. Mizzou would be an instant rival with Illinois.
I'm starting to think that the B10 is going to stop at 14 teams. Obviously Notre Dame is the big fish and the BTN still wants a foothold in the NYC market (Rutgers). I think the B10's next move is to offer membership to Rutgers to destabilize the Big Eas,t and force Notre Dame to join.
Once that's accomplished the B10 got everything they wanted, ND and NYC television market, plus the bonus of Nebraska.
I think Mizzou at this point is an after thought. Let's not forget that ND has said they don't want to give up being an Indie unless they are somewhat forced to. By the BT picking up Mizzou that isn't going to change ND's feelings on staying on their own.
Now if the Big Ten gets a Rutgers, a Syracuse or both out of the Big East then ND might have their hand forced to make a move since both of those schools are in the same conference that ND is in for the rest of their sports.
Sooner or later (seems to be sooner if Nebby to the BT does happen Fri.) when the Pac 10 adds the Big 12 south teams to make 16, the SEC, and the ACC aren't going to sit around, this is what ND was talking about with their hands being forced.