This is something I'm not considering, and doubt that I would ever consider, but wanted to know if anyone else had thought of it. Is there anything that would stop a coach from managing two teams at the same time by constantly flipping back and forth between the two schools every other season, and balancing the recruiting classes so that all of the players are signed in the seasons that you would have each team? I suppose you would probably need to do this in D3 to reduce the likelihood that a different coach would snatch one of your teams in the off-season.
I don't see how this would violate any fair play rules since there aren't any actual advantages from doing it. It's actually a pretty dumb idea to begin with, but seems like it could be a fun/silly challenge for a coach looking for something different. At the D3 level, seems like you could theoretically build two teams that would be in the national tournament every season, maybe win a game or two. I doubt it'd be possible to actually build two title contenders simultaneously though.