I know that it won't work from a money standpoint, so this isn't really serious, but from time to time, I'm intrigued by Cincy and Memphis.
The North Division in football would be hot garbage (KSU, KU, ISU, WVU, Cincy, Memphis), but that would be tremendous in basketball.
I think there could be a slim chance Memphis and Cincy could be competitive in football, but Memphis intrigues me due to the number of times the city has gone after the NFL and failed. Part of me wonders if they were invited to the Big 12, we could get assurances that the city of Memphis would commit to significant renovations of the Liberty Bowl.
Also, Memphis, and that General area, is a huge hotbed of recruiting talent.
But the basketball. Man, that would be tremendous.