I think judge Manchester is very likely to be red john...he easily has the power, money and influence for all this...also, something is seriously cookin in that poker group...
In season 1 episode 11, jared renfrew writes "he is man.." on the wall....dat could be manchester,...
also, in the same episode at the very end, red john calls jane and laughs....if we hear the laugh of manchester during the poker game in season 5 episode 14, its the SAME laugh....
One more thing...wen bosco was in charge of the red john case, red john kills him to give the case back to jane.....now in season 5, judge manchester effectively does the same when the case is almost taken by FBI....