I would find it strange if Bertram is RJ. If Bertram is RJ why on earth would he hire a PI to bug the CBI? Why wouldn't do it himself? 

A question rather than a theory. Do any of the suspects play an instrument? Specifically a stringed instrument.

4-novemebr interview with Simon Baker

http://live.huffingtonpost.com/r/segment/simon-baker-the-mentalist-/526801b8fe344421c300023a

Once again, rather than a theory, this is more of a thought.
Something struck me as odd when I was going over the recent episodes in my head, and it was kind of bugging me: exactly on what grounds did Patrick assume that Kira (private investigator from The Red Tattoo) was hired by RJ? I couldn't remember, so I went and re-watched the ending of episode 5.

It turns out, the moment Cooper (was that the name?) says he/Visualize did not bug their office, Patrick says that Kira was hired by RJ. It was the logical conclusion at that moment, since he wasn't aware of the existence of Tyger Tyger.
Now, in view of the recent events, we know that the three dot tattoo is the mark of the organization. And since Kira said nothing else except that her attacker had that tattoo, there is really no evidence to suggest that it was Red John.
Was the person who hired and killed Kira from Tyger Tyger? Most probably. Since they seem to have been keeping tabs on Patrick, they have enough motive to want to be in on whatever his team does (although, the reason for sending a private investigator when the members are all in law enforcement eludes me completely, same goes even if it's RJ's doing).

My point is, we can't say with certainty that RJ was involved, even though Patrick's assumption is understandable. Hence, the tattoo clue might also be bogus.

Okay, so if you think Red John is NOT a member of Tyger Tyger click green , if you believe he IS a member of Tyger Tyger, click red , just to see what everyone thinks.

new scoop from Tvline.
Any news about the
next episodes of The
Mentalist? About the
end of the Red John
arc? –Sal
I am able to rule out one
wild theory — that random-
ish CBI wonk Ron will be
revealed as Jane’s
nemesis. (Some have the
idea that “Ron” is short
for “Red John,” after all,
and the guy does seem
omnipresent.) “That’s a
very clever theory, but
there are no games being
played,” EP Daniel Cerone
assured me. “It is one of
the suspects [on Jane's
list].” Watch for the next
episode of Spoiler Alert!
for my official Red John
prediction, with a twist.

There are many theories that claim RJ is Van Pelt.  It is not:

The last ep of season 1, the sheriff and PJ walk into an abandoned house and PJ almost walks into RJ.  He juggles the door handle but the door is locked.  Behind the door, we see a shadow who is shown leaving a table with  cup of tea on it.  The sheriff is the son of RJ's associate and RJ is staying there. 

While this happens, Rigsby and Cho discover the true identity of the sheriff and call Lisbon.  When she doesn't answer, they call Van Pelt who is at the office.

So, RJ is not Van Pelt or any member of the team.