Interesting -- looks like the SEC is planning for a "6-1-1" conference schedule (6 divisional, 1 permanent cross division rival, 1 rotating cross division matchup):
SEC official Larry Templeton confirms plans for '6-1-1' scheduling model - CBSSports.com
If conferences do end up going to 16, it does seem likely that they will just become two 8-team mini-conferences. I think the Pac12 and Big Ten got things right with 12 teams and their conference scheduling agreement. 14 teams is too big and doesn't allow for any type of reasonable scheduling arrangements.
The Big East sat at 8 for way too long. I'm not sure if it would have mattered, but if they had 12 at the time of the ACC "raids," they would have had a deeper bench to work with. I hope the Big 12 gets up to twelve and holds tight.