If you are worried that the ACC will lose its spot at the Big Boy Table, attack the weakest power conference in the game: the Big 12. The stability of the conference hinges on Texas. Let's not forget, this "conference" (Texas and yes-men) was on its deathbed recently. Make Texas an offer it cannot refuse (if it's ND-ish, so be it) and be the most attractive home for Longhorn athletics.
It won't guarantee long-term stability of the ACC, but it will destroy the Big 12 and keep the ACC in the top four.