Vito Genovese was refered to as Don Vitone..
A relative of Don Carlo Gambino was called Don Paolo, however, he never became a 'don' (boss).

And I thought (not sure) that Sal Maranzano was called Don Turridru by Bonanno is his biografhy.

But bossed were never called by their last name as in The Godfather. Don Vito, Don Michele and Don Vincenzo instead of Don Corleone.