UND baseball is one solution, but so is Summit League football. Perhaps the five Summit schools invite Poly and UC-Davis to form a 7 team league. That also gets the Big Sky down to 11 (with Idaho's impending arrival) leaving the door open for New Mexico St. Would give a lot of options for non-conference games between big sky and Summit schools, and the MVFC teams would have non-conference openings as well.
If Miami and Western Michigan were to depart the NCHC, even hockey sponsorship could come in to play.