Not really suspecting anyone yet, but just a theory on Partridge.

I don't yet buy that Partridge is out of the picture.  There are some similarities here, such as weight, size, and especially voice which doesn't seem to be masked by any kind of device.  Red John knows Patrick has a list of 7 suspects and one is him, a good idea might be to kill off one on that list, him, obviously this would have to be faked.  Think about it, Lisbon found Partridge, then got knocked out, almost looked like she was tripped, i.e. partridge pulling out her legs from underneath her while talking to Patrick.  We know RJ has many connections, could be working with someone to fake his death, we have not seen/heard anyone on Lisbon's team investigate the body, they might just be going on someone else's word, as there's no real reason to think otherwise.  Remember, in one episode, Rigsby faked his death without no one knowing.  Keep in mind also, that Partridge repeated a part of the poem, which PJ and team most likely never mentioned to him, at least they didn't in any episodes, even if RJ told it to him, why repeat it to Lisbon?  Also, why kill Partridge, what would be the point, especially due to his incompetence, I don't see Partridge giving him any real reason.  Not saying I necessarily think it's him, just that I think it's still within the realm of possibility, we'll have to wait to see for sure.