I know a bloke called marcello and it just gets shortened to marc. Just depends on what he is happy being called once he gets a bit older, my name is Elizabeth and at various times I've been liz, libby, beth, and lizzy! Xxx
I have just run these by my DS8 (who was on his way back to bed before I get flamed for him being up so late!!) his off the cuff NN's were Marcy for Marcello, Rocky for Rocco and Raffy for Raffaello. I won't tell you what he said for Romeo... Thought that a child's point of view might help, especially as no matter how hard we try it is they that bugger up our lovely names in the playground - his name is German btw and it is constantly messed about with!
I personally love Raffaello. I used to work with a gang of utterly gorgeous Italian men (so with name association in mind!) how about Fabian, Giacomo or Francesco?