Sorry it's taken me so long to post on this topic Giorgio I havn't really found any new names i'd add to it. But i've just been looking through old posts and I saw a common choice for Andy Garcia to play Giuliano and Jonny Depp to play Pisciotta. Whilst both may be too Spanish for the roles they've both proven themselves to play Italians before and it's worked for me.
Zaza your idea for Paul Sorvino to play Don Croce is awesome. Great idea. But I can't warm to Dennis Hopper playing Andolini. I think he's much to old for that role.
Scene i'd like to see. Dunno, it's a hard one but i'd like to see a really questionable scene of the Portella Della Ginestra disaster. Where the audience cannot put full faith into whether Giuliano was behind it or not. I don't know how this would be done but some talented director out there could do it.