I don't know if I posted this before, but last year a rumored plot synopsis leaked. I think certain elements of it have been debunked by what we've see, but the framework does seem plausible. This could have been based on an early script prior to revisions that Scott and Lindelof made, or it's completely bogus. Still, interesting read.
http://boxofficebuz.com/news_full.php?id=287