If there are 64 teams, I can see no permanent conferences or divisions, but what about different ones every year? Eight 8-team conferences, play 7 games within your own conference and 4 non-conference games against another designated one (or two each against two other ones). It would be more like the NFL but we could crown a truer champion this way.
The change of teams in each division every year would be completely unique to American sports but, I think, very cool.