Brett Partridge is Red John. Period.
When Partridge was found by Lisbon, the GPS Tracker in Van Pelt's monitor was showing that the suspects were far away from Partridge localization.
So this show us two things:
1- Red John is not the other 6 suspects, clearly the ones that have the three dots tattoo are part of the organization, but not RJ.
2- Partridge is not dead, he faked his death. Partridge was the first taken out of the list by RJ, why? Because Red John is a safe guy, aways one step ahead.

So Partridge will show up on S06E08 ('Red John') and 'surprise' everyone. He is the only one in the suspect's list that appears since the First Season. C'mon, the other ones would be a huge disapointment.

(Sorry for my bad english.)