I think it must be Reede Smith. During Red John appearance in season 2, the actor Drew Powell was thinner. He now has short, straight hair and is a bit fat. He easily shows his anger, but Heller stated in an interview that RJ could be him with psychopathic anger masked by anger. That is the best way to hide it. Everyone believes that since he cannot hide his anger, he cannot be RJ as Rj is cool, calm but who knows Smith might be putting on an act as displaying his anger.
He will be revealed as Red John. He might not fit the exact description of Rosalind Harker. That is the point, how can a blind woman tell the height of someone. Look at Bertram, he might have worn a wig to pretend he was someone else. He sounds creepy at times and he walked out from the mall in Season 3, because he knew Jane would find out the fake Red John. His hands and Haffner's hands are the ones that match Roy's when he visits her. One more interesting fact is that the actor who portrayed RJ when he visits Harker was none other than Jane.