I apologize for the necromancy, but the forums won't let me send PMs yet. I would have just PM's Yann instead of raising a thread from the fossil record. I also don't see a rules post forbidding the resurrection of fossils.
Yann, I'm interested in the examples you posted earlier in the thread. Your dropbox links seem to have gone stale. Do you, by chance, still have them?
I too am looking to set up an RPG with branching dialog, and while I see a bunch of ways to do it, and Yann's descriptions have been informative, I think I can still learn more from an example. My goal is to set up a system that it will make it as easy as possible to set up dialog for hundreds of conversations, even if that means writing a plugin. It looks like all the dialog will be in one array though. Is there a way to make an array local to a specific layout? I would like to deal with each layout separately, since we seem to be making levels in no particular order.