Half(the old days featuring Sonny) of GF 4 is already written...Puzo said Deniro and Andy Garcia have copies of it...atleast thats what he said on the DVD interviews...the hard part is finding a good enough "present day" story to give to Vincents character...maybe Vincent Corleone restructuring the family and making his own name with Michaels help..?? Who knows...someone needs to think of something already...