A few weeks back I designed 3 10 team leagues from catholic/christian schools. It would involve regulation and promotion. I'm sure there's no chance it would occur, but it's something to dream about.
1. Georgetown, Marquette, Notre Dame, Providence, St. John's, Villanova, Xavier, St. Joe's, Gonzaga, Temple
2. Dayton, St. Louis, Portland, Creighton, DePaul, Manhattan, Saint Mary's (CA), Duquesne, St. Bonaventure, La Salle
3. Detroit Mercy, San Diego, Fordham, San Francisco, Iona, Holy Cross, Mount St. Mary's, Sacred Heart, St. Francis (PA), Santa Clara
Edit: I forgot Butler and Seton Hall in that first group, so, would need to knock someone off for them.