Or you could put ND in the Pacific Division to preserve the USC/Stanford games as every year without needing a crossover, something like:
USC
Notre Dame
Stanford
UCLA
Washington/Oregon
The problem is then finding a second marquee football brand for the Atlantic Division if the B1G stops at 20 (and ND doesn't head East), unless you are willing to entertain Miami or North Carolina on an Island in the Atlantic Division. Miami would be on an island all by themselves though in every respect, not sure they'd want to do that, but something like:
Penn State
Miami/North Carolina
Rutgers
Maryland
Northwestern/Illinois
I don't see how you can use an ACC model w/ 20 and determine the conference champion without relying on weird tiebreakers or subjective polls - to me you have to settle the conference champion on the field, and the only way to do that is a round robin format with divisions. If someone can show me how you get legit on-the-field conference champs with a 20 school conference without divisions, then I might change my mind, but every proposal I've seen would not accomplish that?