The ACC's big problem is that the thing that made conferences originally make sense--geographic proximity and coherence--is no longer what makes them profitable. It's all about TV now, which calls for name brand matchups between good teams, and/or geographic spread across multiple time zones. A splinter conference of eight ACC members wouldn't fix that, it would only make the pie slices a little bigger for each member by cutting out the dead weight. They could join with half of the Big 12 members, perhaps, but at that point you'd be cutting the pie 16 ways again and switching BC and Syracuse for Colorado and TCU isn't going to get you into the realm of Big Ten money. If you're going to the trouble of killing the conference it's only worth it if you join the SEC or Big Ten.
I think most likely the biggest brands will just jump and go to law to stall on the financial penalties, gambling that in the wreckage the remaining members will fight each other for the last four-ish life raft spots in the Big 12 and dissolve the conference.
But these questions are less important than what the overarching governance structure of college football is going to be, anyway. SMU is probably screwed no matter what, but the Big 12 might be too at this rate.