I am fairly confident that Brett Partridge is Red John. He was there from the beginning, which I feel is crucial to the story and he is on the list of suspects.

Everyone knows how Red John likes to use artistry and "The Tyger" poem. After hearing that Partridge was dead, it immediately made me think of "And Then There Were None" by Agatha Christie. For those of you that haven't read it, its basically about 10 people trapped on an island and each of them die one by one until there are none left so the police couldn't figure out who the murderer was.

This might also answer why he calls himself Red John, because the murderer in the novel is Justice Lawrence JOHN Wargrave whose death is described in the poem as "Four little Soldier Boys going out to sea; A RED herring swallowed one and then there were three." A red herring is something that basically misleads you from the truth. In the novel, the judge faked his own death to remove any suspicion that it was him. I believe that Partridge did the same thing. It seems like a perfect parallel type of artistry that Red John would use. I believe Jane will go through the list of 7, eliminating each suspect until there are none left. But actually Partridge is still alive, hence the red herring.

Of course I could be wrong and it could be a complete coincidence.