Ray Haffner isn't Red John because he could easily put bugging device by himself. He wouldn't need Kira Tinsley. So could Gale Bertram. (I had already eliminated Bertram when Reede Smith ordered him something but this is also another evidence that proves he is not RJ)

That leaves Bret Stiles, Sheriff McAliister, and Reede Smith...

Bret Stiles has been eliminated almost everybody due to his age. He is really too old to be Red John. He isn't Red John.

And I think Sheriff McAllister is also too old to be called "middle-aged". He isn't Red John.

As you all know Reede Smith is very tall and big man. If you look carefully, when Kira Tinsley opens the door she isn't looking at a person who is as tall as Reede Smith.

I think Red John is Brett Partridge. His appearing in Red John cases, his voice, other physical properties, character, relationship with Jane and even his death are strong evidences. And as an interesting clue, see what wikipedia says about partridge bird. It avoids high places... en.wikipedia.org/wiki/Partridge (discovery of this partridge bird information doesn't belong to me, I saw it from someone's theory earlier)