I've been interneting it today and have seen three distinct rumors making the rounds. First, KU & ISU to the BT; second, two former Bight 12 schools, presumably KU & ISU + 4 Pac 12 schools--USC, Colorado, Washington, Oregon (this one because UCLA can't politically leave Cal, and Stanford too PC), and third, six PAC schools---those 4 + UCLA & Stanford.
OK State is not being mentioned as a 2nd Big 12 team due to academic standing.
I am surprised at ISU being mentioned so much, but I could see it if #2 or 3 happen.....can't see it as KU + ISU only.
I have seen no internet rumors to the effect that Big 10 will stay at 14.
For those interested in this, the Kansas 247 site is a hot mess of rumors. You can start on page 112, because I've brought you up to date.