What was the nickname of the real gangster whom the Godfather's Morris "Moe" Greene name is a partial composite of? 
Moe Greene:  The character's name is a composite of real Las Vegas mobsters Moe Dalitz, or possibly Moe Sedway, and Gus Greenbaum. Moe Dalitz:  He was often referred to as "Mr. Las Vegas".
Mr. Las Vegas