I don't think that Reede Smith is Red John. Reede Smith is too fat to be Red John. In my opinion he's Red Johns "Friend" in the FBI. I think he was the guy, who told Red John about Janes Plan in Episode 4x24 "The Crimson Hat" and he was very nervous, when Jane said he's very close. Remember that Smith asked Bertram how close Jane is.
How do you find this theory?
plausible
unlikely