I dont believe that red john is ray haffner. In the episode where teresa lisbon refuses to join haffner's private firm, haffner asks her if it is because of Jane. Haffner tells lisbon that when jane finishes catching red john, Jane is going to leave the firm. Haffner gives this as incentive for lisbon to join his company. Now why would haffner say this if he were red JOHN?

Also R E D J O H N has 7 letters. Jane also compiles a list of 7 names (just an interesting thought =) )Honestly I dont think that red john is any of the 7 guys..