I don't think it's any of the 7 suspects that Patrick believes. Why as the director of the mentalist would not want any viewers getting it right and when red John is revealed all viewers will be in shock.

Now it makes you think how did red John know the 7 that Patrick would choose. I believe it's someone related to Patrick ie a lost brother he never knew or his dad but has had surgery.

Other reasons why it ain't the 7 is many of them it's been to obvious for some of them it is red John and the others are not smart enough like Patrick. As it was said in an episode red John is very much like Patrick