I think Red John is a syndicate - possibly linked to the poker group that Lisbon has been invited too. The fact that Red John is always one step ahead of the authorities, always seems to be well informed (think when he rescues Jane from students and other occasions) obviously has money and connections (think FBI mole in Crimson Hat) and has been able to murder with impunity all these years. I think there is a Red John who may be Bertram or Brett Partridge who originated at Visualize who is the lead actor but only many different Red Johns would be able to pull off and get away with these various crimes and schemes.
