Two Gunslinger developer diary videos have been released. In the first video, writer Rafal W. Orkan reveals who was the inspiration for Silas Greaves from real life and Pawel Blaszczak talks about the music, among other things. In the second video, writer Haris Orkin talks about Gunslinger's background and movies that provided inspiration. "I think that there's a chance to make another game in this franchise. And this time go even bigger." Gunslinger has been a success so it would be a crime to not make another Call of Juarez game :)
"How the West Was Won Again"
"The Story of Call of Juarez Gunslinger" by Haris Orkin