rat snake? maybe?

Well, if nobody here knows, and that guy from Indiana hadn't seen one like it, and I know crap about ratsnakes.... Maybe it's a natural hybrid?

Might try posting the pic on Kingsnakes ratsnake forum and see what they think.

Okay, I've never even attempted to guess a species when people post pics - because I know I'll be wrong. However, one pic I found that resembled yours was a Texas Rat.