My guess is Red John is the prince who plays backgammon with Patrick.
In episode 21 of the first season, when Jane and Cho look for a con woman(Brooke Harper) and they go to the Backgammon Club.There, waiting for Brooke, we see Jane playing with someone who we learn is a prince a moment later when Jane tells Cho "First prince I ever met".
It's a short scene, one of those you watch and never think too much about it.And then it got me thinking, what is a prince doing in USA, especially in a backgammon club?Of course, he could just be a prince who really likes backgammon and was visiting the United States for some reason.
But the thing is, even though we don't see it, they are very cordially with one another, Jane rarely is that way to all the rich people, so my guess is they surely shook hands.And after that they went right straight to the backgammon game.And Jane was winning(20.000 dollars actually).When was the time to go, Cho stopped Jane from taking the money from the prince and Jane explained how he cheated to win.Here's the thing, the prince doesn't really look mad or upset, more like impressed, intrigued or uninterested.
So I thought, here is a prince who probably visits USA on a regular basis, to play with his club peers and who sure shook hands with Patrick, he's super rich since he's a prince(even if he's not, he's rich enough to pretend he's a prince) and in the eventuality of him being Red John, he's smart enough to play Patrick and let Patrick win, maybe he wanted to test Patrick to see the exact extent of his skills.
After this short scene, we never see him again, but who says Red John has to appear on a regular basis like CBI Ron or at least a couple of times like Mashburn.I don't get why so many people are in a hurry to not take into consideration these smart and/or rich characters that only appear once like Max Winter or Gabe Nyland.Maybe one of them is Red John.
So to recap:this guy is a prince or pretends to be one, he's rich, possibly smart(if he's Red John), spends time at the backgammon club among other rich people with powerful influence all over the states(Red John's connections) and there's a strong chance he may have shaken hands with Patrick(Lorelei said "it's a surprise you two didn't become lifelong friends when you shook hands", well maybe they don't hate each other, they just met once and there wasn't an opportunity of meeting again).And you can extract these information just from seeing him once in a short scene.
I am not saying he's clearly Red John.But you have to stop look only at the big characters like Mashburn, Minelli and the others and realize that maybe Red John was a one scene character that only was present sometime in the past enough to see him and that's it.That way when he's revealed we'll be like "Ah, he was under our noses the whole time" or "Why didn't I see that?".
Keep in mind that Red John doesn't have to be someone who keeps appearing and who is powerful, rich and smart.They may all be red herrings, which I am pretty sure they are.Look for these little clues that go unnoticeable.I watched that episode 4 or 5 times(I am addicted to the show so I keep rewatching it) and only the last time I saw the prince I realized there's a good chance he is Red John, it would also explain why Red John doesn't kill so often(he's busy and when he wants to blow some steam off, he kills someone or plays with his old backgammon buddy Jane).
