Start reading this theory with your mind set to RED JOHN IS WALTER MASHBURN.

Red John(AKA Walter) has no female accomplices,he slays women rape them and paint with their blood.

Throughout the past 5 seasons we knew RJ has many male accomplices almost everywhere CBI,FBI,DA and visualize ,he never kept a woman alive except for three and only three Rosalind Harker , Lorelei, Kristina Frey.
 
He never kept a woman alive for as long as Lorelei or even still alive (Kristina and Rosalind ).

Pay attention to what  Walter is saying at 0:34 in this video:
 http://www.youtube.com/watch?v=oPVASLzF1Z8

"My second..nah my third wife was into this .....) he was referring to Kristina Frye as she is the third female that RJ kept alive.

Now lets see what we can match from the clues in last night's episode:

He has a fear of Acrophobia (fear of hights) : Unconfirmed.
He is middle age : Walter is.
He has no living family but many friends he relies on : Walter is .
He is a a excellent whistler : Unconfirmed.
He is a damage and narcissistic individual : Jane couldn't read him and yes hes damaged.
He doesn't deal with conflict and adversity easily : Unconfirmed.
He speaks rather convincingly when lying outright Walter is.

And if you watch Walter scenes he wears red shirts , red Ferrari , red boat.

I am convinced that Walter is RJ but i don't think the Walter character had time in the show to develop for the audience to enjoy and be satisfied when RJ is revealed to be him.

Seriously.  Don't even laugh. You heard the 4 names mentioned at the end. 

1. Ernest Matthewson
2.  Miguel  Livario
3.  Jay Roth
      and .................drumbeat.............................
Mitchell Livingston WASHBURN!!!

WASHBURN/ MASHBURN-------   Ugh,  whatever.  Also, isn't funny how the wealthy love using hyphenated names?

PLUS>>>>  Tonights episode was about avionics!?!?  Hmmmm?  Food for thought?

I do believe it is Walter Mashburn, .  In the episode Red Line he is someone who "reads" Lisbon right off as Jane would do.  He is amused by Jane and challenges him and Lisbon by saying "catch me if you can" even though he knows he's was not the killer in this particular case.  He seems to want to be Patrick's " buddy" much like Red John who wants Jane on his side.  When Jane finally does catch the killer in he is impressed and finds it exciting.  He also tells Jane "maybe next time I'll be the killer" 
Also, as we know Red John is a character that seems to be able to get anyone to do anything.  This Mashburn character literally "charms the pants off" of Lisbon in a later episode which is not easy to do.  

IN episode 4 patrick reveals that the list is fake.....walter mashburn=RJ is my theory or suspect...http://www.spoilersguide.com/the-mentalist/season-6-episode-4-red-listed-guide/     hightower RETURNS !

I Win.  I was right.  The small minority of people that said the list was fake have be vindicated. Jane planted a fake list and the real list has Richard Haibach on it.  All the favorite suspects will likely be on it:  Walter Mashburn, Dean Harken, Ardiles, Ellis Mars, etc.  I do suspect that the real list will have less than seven names though.  RJ is going to be Mashburn.

The Mentalist 6x04 Press Release.

Source: CBS

JANE REVEALS THAT A LIST OF FAKE RED JOHN SUSPECTS HE PLANTED WAS STOLEN, AND THE TEAM REALIZES THESE MEN ARE IN DANGER, ON “THE MENTALIST,” AT A SPECIAL TIME, SUNDAY, OCT. 20
Aunjanue Ellis (“NCIS: Los Angeles”) Returns as Former CBI Director Madeline Hightower
William Mapother (“Lost”) Guest Stars as Richard Haibach, One of the Men On the List
           “Red Listed” — Jane reveals that a list of fake Red John suspects he planted was stolen, and the team realizes these men are in danger, on THE MENTALIST, at a special time, Sunday, Oct. 20 (10:30-11:30 PM, ET/PT) on the CBS Television Network.
CHEAT TWEET: 7 more #RedJohn suspects? Or are there? What is Jane up to? #TheMentalist Sun 10/20 10:30pm 
SERIES REGULARS:
Simon Baker     (Patrick Jane)
Robin Tunney     (Teresa Lisbon)     
Tim Kang     (Kimball Cho)        
Owain Yeoman     (Wayne Rigsby)     
Amanda Righetti     (Grace Van Pelt)

GUEST STARS:
Kevin Corrigan     (Robert Kirkland)
Drew Powell     (Reede Smith)
Aunjanue Ellis     (Madeline Hightower)
Sloan Robinson     (Ruby Hightower)
William Mapother     (Richard Haibach)
Tim Sitarz     (Rick Dort)
Rolando Boyce     (Van Driver)
Jeffrey Cannata     (Agent)
Myles Cranford     (Janitor)

WRITTEN BY: Rebecca Cutter
DIRECTED BY:  Eric Laneuville

IMO, RJ is not on the list and Jane knows that. I think he have a bigger plan which include that toothpick scheme.
Jane is leading the game for quiet some time and is doing that very patient and secretly so RJ think he have an upper hand.
He knew that Lisbon will tell the team about the list, and also she will put those gps devices.If Jane believe in that list he would never told Lisbon about that.
Everything he's doing is with some purpose and plan, now there's no such a thing like coincidence.
And also 2 other things looks like clue from episode ending:
1. That car wasn't some random car
2. There was something abut the sink 

Mashburn or Minelli plus Kristina Fry

My theory is based on what I think would be great to see play out. If it's Walter then Lisbon would have to deal with the fact she slept with Red John or, Walt is Red John and Lisbon is another one of the many women he uses and the scene we see isn't the first time they've slept together. I think I'd prefer to see her deal with unknowingly sleeping with him though.