Battlestar Galactica speculation

Warning - may be spoilers, may be complete codswallop.

I came up with this as a throwaway on Pandagon, but the more I think about it, the more it makes sense.

The major remaining mystery of Battlestar Galactica as we head into the final season is - who is the fifth Cylon - the one missing between Lee Adama and Tigh in this photo:



Some clues already given:

- It's been noted that "The fifth Cylon will be "organic and satisfying. It won't be some day player from Season 1." says SciFi Channel VP Mark Stern.[5] Stern describes it as "delicious" and "one of those things that are right under your nose and you don't expect it -- but it makes total sense." He says, "it doesn't feel arbitrary, It feels like it could have been planned all along."[6]"

- "The First Hybrid says this about the final Cylon:
"The fifth is still is in shadow, drawn toward the light, hungering for redemption, that will only come in the howl of terrible suffering." (Razor)"

- "D'Anna Biers's vision of the Final Five led her to speak of "the one who programmed us." (Rapture)"

My guess is that the fifth Cylon is, in fact, the Battlestar Galactica itself. I'd rate it at about 30-40% probable - it seems silly on first glance, but the more I look at it, the more it seems possible, and both a twist and an organic part of the whole series.

Consider:
- The purpose of the final Five is to find Earth. If Galactica is pulling their strings, this would explain the musical episode. And what else is more likely to be there if the fleet succeeds?
- The Galactica, using the other four and perhaps Baltar's Number Six as unwitting catspaws, has been manipulating the humans and also manipulating the Cylons, without the Seven being generally aware of what has been happening. The Cylon pursuit of the Fleet has been a spur towards the goal of finding Earth.
- There is no reason why a Cylon should look human - at all.
- The key argument against this theory is that it is a military ship, presumably with every inch maintained on a regular basis. How are you going to hide a Cylon brain on board? This makes sense until you consider that both the ship's chief petty officer and its second in command may have been manipulated - the two people most able to conceal the truth.
- The directors have said that they were leaving clues, and then they came out with the "Last Supper" picture. This conspiciously had an empty place. But, then again, perhaps they're just enamoured with their own cleverness enough to leave the clue in plain sight - look closer and it is not an empty place at all. The Fifth Cylon is right there...

Okay, so it seems unlikely. But, considering it, it is a narratively brilliant stroke, and considerably more satisfying than having Zarek or anyone else turn out to be the candidate. I'd wager on it if anyone would give me two to one odds.