What D2 colleges have the highest number of basketball walkons?

My son is a high school junior and is pionate about basketball and a good ball player. If he doesn't get any 'looks' (only 5' 10") in the next year, anything he can do to increase his chances? He doesn't care what college he attends (if not D2, then D3), but he just wants to play basketball and I'm wondering if there are any stats out there that indicate highest number of 'walk ons' over a time period, or other tips. He has good grades too!