In the past I would have suggested Rutgers, but Iowa, despite the gambling suspensions, probably takes the title with 7 out of 10 starters being transfers (Cruz, Teske, Woods, Voinovich, Franek, Swafford, and Caliendo).
But I'm wondering if another school might dethrone them for the title of "Transfer U"?
My school, Penn State, sports 3 transfer starters (Nagao, Messenbrink, Truax). Note I don't count Kerk as a transfer since he never actually competed in another school's singlet despite previously committing to other schools.