Just brainstorming here ... but what if a school like Kansas agreed in 2014 to join the B1G when its GoR expired in 2025. Would the B1G take UConn in 2015 and play at 15 for ten years waiting for Kansas to join? Supposing UConn adds enough value in the northeast to improve the TV contracts. What if Texas, Oklahoma, and Kansas agreed? That would be too good to pass up.
Football scheduling with 15 teams may work out about as well as 14. 3 pods of 5 teams, 4 games in pod and 5 rotating games among the other ten pod members means every two years you play the whole league and every four years do home and home. You just have to choose a method to pick the conference championship game participants -- two highest ranked pod champions?
Current NCAA rules dictate a CCG may only be played for conferences 12+ that are divided into divisions that play round-robin within the division, so that break up won't work. Uneven divisions can theoretically work but will be hard to get buy in from all Big Ten members because this will mean that the Western members will be playing Michigan/OSU/Penn State even fewer times for at least a decade.
The reason why the 16-team pod system can work is because they can theoretically combine 2 pods to form a division for each season and play round robin, which still falls under the current rules.
I don't think it'll be trivial to get the official rule changed since you'll first need to prove why the division setup isn't sufficient to crown a conference champion - assuming 9 conf games a year the current system scales nicely to 20-member conferences - it's only once you get above that number that the system breaks down and I don't think any conference is seriously going up that high.
I guess if D4 becomes a reality and comes with new rules that changes this equation your scenario can work though.