I think ultimately it will be patrick Jane…..he is very intelligent and loves games!! there have been clues through out the series that have made me think that but ultimately one thing that makes me believe he is RJ 
-he is that intelligent and in all this time he has never come close to find RJ which i don't understand
-unless RJ is as smart or smarter than Patrick there is just no way he would have also known the list
-RJ would have gone to great lengths to ensure his associates never turn on him and many have proved that but yet somehow Jane got/almost had lorelei on side
-they both have very similar personality traits

and i think that it has all been just one big game for Patrick Jane because deep down even though i love patrick he is just a very narcissistic and intelligent psychopath!! 

therefor PATRICK JANE is RED JOHN.