Jesse Custer: James Franco
Tulip O' Hare: Brittany Murphy
Cassidy: Dominic Monagahn
Herr Starr: Ed Harris
Saint of Killers: James Remar
Im not too good with messing about with images and just used paint but sure, you get the idea anyway ;)
I was going to cast Arseface but and a few others but call this a start.