I have raised this point before, but I don't think we have ever taken this seriously. However, given the events of Happily Ever After, it must now be a serious proposition: When Desmond revisited his past in Flashes Before Your Eyes, he apparently changed the events which had happened to him & Penny. This means that the "original" Desmond from the OT hatch (prior to the failsafe detonation) originated from a timeline in which events played out completely differently to those we have seen in the OT.
Many people speculated that this might have been the FST; however we now know that this cannot be the case as as in that timeline the island did not exist, and we know by FS 2004 FS Desmond is not on the island (even if he had somehow 'crossed over' timelines), and in the FS he doesn't even meets Penny (or Eloise) until Sepember 2004.
The question therefore remains as to what exactly the timeline was where Jimmy Lennon "originally" hit the Barman, and Desmond "originally" did NOT buy the ring. This is a Completely Different Timeline (CDT). The question now becomes are there any other fragments of this CDT lying around?
This would have to be a timeline in which events played out without Desmond making any changes to his past. One of the changes that Desmond made was to give Faraday the settings for his machine which allowed Faraday's time travel experiments to succeed earlier than would have been the case. Desmond was only able to make these changes after Faraday arrived on the Kahana, which only detected the position of the island as a result of the failsafe blast, which was a direct result of the losties' actions. They arrived on the O815, which crashed as a direct result of Desmond failing to press the button after he killed Inman. In other words, this CDT would be a timeline in which O815 never crashed, and no time travelling losties went back to Dharma times, and there was no Jughead Incident in 1977.
However as we have seen above this cannot be the FS.
So what, or more particularly, where is it?