I have been watching all the episodes of this great serie and i believe Red John have never showed himself to the public "yet"
All the caracters we have seen untill now are just people working on catching RJ or working on helping RJ but clearly RJ himself have not been on the show yet.

I think that Miss Schultz of the FBI and that guy in the limo are just the high officers helping RJ, dont forget patrick mentioned this already a few times.... remember that RJ's only chance of not getting cought is help from the inside.

The thing is..... this whole serie is not about Patrick Jane but about Red John ( think about it ) the most exiting episodes are the ones with RJ in it, if the writers of the serie put out RJ face now it will defenitly mean the end of the serie.
I just think the guy in the last episode  Wth Miss Schultz in the limo is gonna shake up some things but cannot be RJ.