It was referenced in this article from the Associated Press in November 2011. It claims that earlier in 2011 BYU had the chance to go into the Big 12 and was in talks with the Big East (AAC), but the TV deal got in the way in both cases. I believe the story about the Big East, but not the Big 12. The timeline didn’t make much sense to me, but anyways, if you all wanted to know where this idea started, it’s right here.