There are many italian films about mafia...

Jonny Stecchino, Palermo - Milano sola andata, Paolo Borsellino, Donne di Mafia, La mafia mi fa un baffo, la mafia dei nuovi padrini and so on...

The Godfahter is an epic film, but it couldn't be real. The sicilian mafia, or la 'Ndragheta, la Camorra, la Stidda, la Sacra Corona unita are not interested in honour, family, pizza, pasta e mandolino. These are things that only Puzo (an italian - american, as Coppola) and Coppola could represent and write.