Jack-ob

This season of LOST is quickly coming to an end, and all the various events of the series are coming to a head. One of the main mysteries throughout the show has been the true identity/form of being of the shadowy and never-fully-seen commander of the Others, Jacob. Since his first mention seasons ago, Jacob's identity has been a source of rampant speculation on the web. I've read entries theorizing that nearly every character seen on or off the island is truly Jacob. Most are ridiculous. The latest and seemingly most credible idea is that Jacob is not anyone we've seen already, as evidenced by ABC's announcing the casting of Mark Pellegrino as "Man #1" for the next and final season, and reports that he was seen filming reenactments of some vital scenes from the LOSTies' pasts. See some non-definitive photos of the set here.

If that's the case, it initially strikes me as less creative than having Jacob be a character we've already seen, but depending on how it's handled, it could be great. If, however, that's not the case, I'll throw in my vote for who it may be (by no means am I convinced).

I vote Jack. First, let's think about the history of Jacob. The earliest indicator we know of his being mentioned was when John Locke in 1954 stormed into the Hostiles' camp, demanding to see Richard Alpert and saying Jacob sent him. We then see in 1977 Richard take Jacob's wishes under consideration in taking a wounded young Ben Linus from Sawyer and Kate, and various times in the original present time of the show, with Ben, Locke, and Hurley visiting the cabin, encountering Christian Shepard and Claire there along the way. Thus, we can fairly assume, Jacob has not always inhabited/lived in/been trapped in the cabin. The cabin was not built until the 1970s or later by Horace Goodspeed (definitive year not known).

If the cabin were built around or before the time of the incident, which we should be seeing in the Season 5 Finale, any number of characters (including Jack) fleeing from ground zero could make their way to the cabin for safety, and become trapped there, possibly in some sort of time-space-shift phenomenon that occurs, thus allowing him to exist in all the different time periods simultaneously. One theory would be that the two separate "present times" currently existing on the island (the 1977 greater-Dharma crew and the 2007 survivors including Locke, Sun and Ben) will be merged again into one, with unknown consequences. Something along the lines of this is supported by producer Damon Lindelof's teaser for the season finale he offered at the Star Trek premier last week: "All I will say is that it is time for the time travel craziness to end," he said. "And once it does end, something very, very surprising will happen in its wake. It is a little bit of a game-changer."

Supporting evidence would include the obvious connection the Shepard family has to the cabin, as we've already seen Jack's undead father, Christian, and his half-sister, Claire, in the cabin. Another would be Jack's status as a detached leader or his people (see also discussion of his tattoos), his in the past being called a "miracle worker" for his ability to heal people, and his name being a variant of Jacob. Then there is also the similar focus on single-eye camera shots of both Jack and Jacob (see pictures, above - top two are Jack, bottom two are Jacob). The eyes appear at least similar enough to be possible.

Finally, on a practical level, it has been reported by the producers that Matthew Fox (who portrays Jack), is the only actor who knows how the series will end (source), thus it would make sense that if Jacob plays a large role in the conclusion of the series, Shepard would already know from his previous portrayals.

NOTE: This is incomplete, and more an exercise of my boredom than a definitive piece of LOST theorizing.

Images from lostpedia.