Last October, after CCG deregulation was rejected, I looked at what's possible under the current rules for a 15-team conference.
This is what I came up with, but this I've replaced Notre Dame with WVU:
Which teams would be in each division? If you're going uneven, the most important thing is to put like-minded teams together. Why? Because mathematically one division is going to play 9 conference games per year while the other plays 8 (it's inevitable with uneven divisions - trust me).
So, which teams want 8 games and which want 9? Let's take a stab at it...
8-game division (7 teams): Clemson, Florida State, Georgia Tech, Louisville, West Virginia, Pittsburgh, Wake Forest
The first four are pretty obvious - they all play an annual SEC non-conference rival, so they'll want to keep at least 3 games free to schedule 2 home games plus one home-and-away (alternating with the rivalry game). WVU and Pitt could probably go either way, but I'm putting them here (with Louisville) to form what is essentially an "ACC West" division
Why Wake Forest, though? Because Wake wants to be able to schedule 4 winnable non-conference games every year for bowl-eligibility reasons. True, this is a very tough division, but they'd only be playing 6 division games (7 teams minus themselves). Depending on their draw from the other division, they could easily win 6 games per year. Besides, Wake is the glue that holds the ACC together, so if anyone would agree to be the 7th team in this division, it's them.
Who does that leave for the 9-game division (8 teams; call it the new ACC East division)? Boston College, Duke, Miami, UNC, NC State, Syracuse, Virginia, Virginia Tech.
BC, Miami, Syracuse and Virginia would all be delighted to play 9 conference games every season - that's what they want now!
UNC would be happy to keep Duke, NC State and Virginia on it's annual schedule (while also playing Wake Forest more often as you'll see in a moment).
Virginia Tech will be happy to keep Miami; whatever rivalry is lost in Pittsburgh could be replaced by Syracuse, IMO.
How would divisional schedules work? Each division would play a round-robin. For the smaller Atlantic, that means 6 games, while the large one would need 7 to complete the round-robin portion. Now, we'd still have 2 cross-divisional games, so that gives us 8 games in the smaller division and 9 games in the larger one... there's just one problem: 2 cross-division games X 7 teams = 14 games, while the 8-team division needs 16 games... what gives? (we'll come back to that).
How would cross-over games be handled? First, every team in the new Atlantic division would play 2 teams from the larger division. That leaves 2 teams in the new Coastal division needing a 9th game, however. What to do? Answer: let them play each other a 2nd time. In other words, each of the teams in the new ACC East division would rotate playing one divisional opponent home-and-home every 4 years. So every 4th year each team would play another division foe twice, while playing all the others just once. (NOTE: If preferred you could have a setup where Miami and Va Tech are not included in this rotation, thus making it a 3-year rotation with BC-Cuse, Duke-UNC-NC State-UVA in some sort of rotation).
15 teams. 2 divisions. Clemson, FSU, GT and Louisville all stay at 8 conference games. The pro-9-game teams all go to 9 games. Enough for everyone to approve it, I think...