I don't have any speculation to who Red John really is, but I doubt it is Patrick as Red John is face to face in a scene at the season 2 finale.  He is masked but that is Red John's voice so I doubt it can be Patrick even though that would be a huge twist!  Also he spoke with Patrick in the season 4 finale and ordered Lorelei to cut off two of his fingers... It is not logical but also, I think someone very close to Patrick is an associate to Red John that is why Red John always has the upper-hand because it would not suffice just having a member of the FBI as Red John's associate as they do not know and do not find out everything that is delivered about Red John or just the actions of the CBI in general...