Red John was hiding in that room behind Lisbon when she found Partridge.

He's to fat to fit inside there.

Simple.

It's Reede Smith.

As far as physical descriptions of RJ go, I can't put too much stock in them.  I bet he has hundreds of disguises and perhaps appears with many personas to different people.  Reede Smith is the wheres waldo character like Bruno Heller said.  R.S. is perhaps just a persona and disguise! Cuz honestly its very interesting if RJ has showed his "true face" to Patrick.  Why would he do that?  It would be unnecessary.  And if he has shown his true face I would say he's Reede (or possibly Mcallister).  Plus I trust Patrick Jane and his 7 suspects list, unless he made it to trick RJ somehow.  Jane knows more about RJ then we do.  Why would Reede be on Patrick's list if he obviously doesnt fit the characteristics of RJ? (it would be patrick trying to trick RJ)
So he's there for a reason and Patrick has reasons for all of the suspects!  Dont get caught up on the minor details!   Try to think about the big picture because a huge theme of the show is that things are always different than they appear on the surface.

I'm am one of those who believes one of the 7 is RJ and the other 6 probably work for or have some sort of connection to Red John.  I don't think Partridge is dead, but I don't think he is RJ either.  Why would RJ reveal himself so easily?  I bet RJ used Patridge to lure Lisbon and then maybe he did kill Brett after all.

Bret Stiles- most obvious choice to be RJ so its not him
Gale Bertram- second most obvious choice to be RJ, it would be interesting if it were him to see                                    how Lisbon reacts
Bob Kirkland- third most obvious
So its too hard for me to believe its one of these three

After Reede Smith, my next choices are Haffner, Patridge, and Mcallister in that order.

Why is no one stating the obvious?? Look at the season 2 finale! Red John is slim. Reede Smith, is fat! Unless Red John put on a lot of weight in between then... Reede Smith is not red John because he's too fat. Simple as that.

I was somebody who thought for sure that Brett Partridge was Red John, but after last night... Obviously it's someone else. Regardless of who it is, I think BP was definitely an agent of RJ. When PJ came face to face with RJ in the season 2 finale, I think he was definitely talking to Partridge, who was posing as RJ. It's not the first time RJ has sent a follower to pose as him. In the season 3 finale, Timothy Carter (the man PJ shoots and kills) claims to be RJ and PJ even believes he is the person who actually killed his wife and daughter, not RJ himself. Also, Todd Johnson (the cop killer who was lit on fire and killed by Craig O'Laughlin) said "Tyger, Tyger" to PJ as he was dying, just as Partridge said to Lisbon as he was dying. Definitely a RJ agent.

As for Reede Smith... 

Bruno Heller said that Red John is a Where's Waldo character in the series, not someone major. I think RJ is going to be someone no one suspected, and going into last night's episode, I noticed that there were only THIRTEEN theories about Reede Smith. Read some of the theories... they're pretty compelling! Especially the one about the origins of the names. That's good stuff. 

I wish to present two ideas:

1. I think we shouldn't arrive in a judgement regarding any of the suspects based on the characters portrayed to us so far. If RJ is one of those 7 - and Heller confirmed he is - I think what we saw so far of that character may have simply been a deceitful act. 

Take Reed Smith, based on his character as it was portrayed to us, none us would consider him RJ material. But if the Reed Smith we know is simply a facade,  meant to deceive every one. Maybe that's what RJ does to hide himself, present himself and perform as a mediocre hot head.

In fact, up until Bret Partridge was slayed by RJ, I thought he could be RJ not because he is weird and has a psycho feel around him, but because Heller portrayed him to us as a youngish, not very charismatic figure, again not really RJ material, if you will.

I think that may be what Heller meant when he said we will be disappointed when RJ is revealed. So I'm thinking: which of the remaining 6 suspects would be most disappointing, if you will, based on the character portrayed to us so far? I think Reed Smith. So maybe Reed Smith is the facade RJ uses.

2. Another reason why I previously thought Bret Partridge may be the one was the tender voice fit the RJ as we heard speak. 

But now Bret Partridge is gone, there is no other suspect whose actual voice sounds anything like what we heard from RJ in those few scenes. Now I believe that RJ used some kind of voice alteration device during those encounters. 

Reed Smith = The Red is me!