BIG 12 I would love it if they got invited too. Utah State is and would be much more of a natural rival than any other team besides Utah. I don't care enough about teams like Colorado State, Boise State, Houston, etc to consider them a rival. Same logic applies to Colorado and Utah.
That said, I honestly don't think USU will get in nor do I think they have earned it based on athletics. I would simply prefer it were to happen over anyone else besides BYU and Cincinnati.