I've always thought a movie on the Scarfo era or Blood & Honor would be awesome and seriously high quality stuff if done right. I mean you don't even need to fictionalize anything the actual true story is great material in itself. I've always pictured Joe Pesce playing a good Scarfo. He is on the older side though (73 years old) so if that wasn't an option then I think Frankie Valli (played Rusty Millio in Sopranos) would be another solid option. In terms of Leonetti, I think that Michael Imperioli (also from Sopranos- played Chris Moltisanti) would be a good fit.