You can go down the entire list of high echelon guys in the Genovese family and pretty much not see one where you wouldn't be shocked if they flipped.
As for the other families...
Bonanno - Vinny Basciano, TG Graziano, Jerry Chilli
Gambino - Dom Cefalu, Nick Corozzo, Danny Marino, any of the Gottis
Colombo - Sonny Franzese, Andy Russo, Ralph Lombardo, any of the Persicos
Lucchese - Niel Migliore, Joe DiNapoli, Matthew Madonna, any of the Pernas or Taccettas