I was just informed of this great post by EW.com PopWatch Blogger Jeff "Doc" Jensen in response to this week's episode of "Lost", and let me just say I'm intrigued. The Island as a "cork" of sorts, keeping a Hellmouth from opening? That's awesome. A "Lost"/"Buffy the Vampire Slayer" crossover might be the greatest thing to ever happen in my life.
Now, Doc Jensen obviously isn't serious about this, but, given what we know about both shows, is it possible? Absolutely. It's been established in the Buffy-verse that there is more than one Hellmouth, most notably in "The Wish" and "Chosen", where the Cleveland Hellmouth is referenced (and yes, I, as a Cavs fan, take some offense to Cleveland being on a Hellmouth. It's not that bad, really.).
And "Lost" could easily take place in the same world as "Buffy". Think about it. Hurley and Miles can communicate with the dead. Sayid and Claire mysteriously came back to life. There's a black smoke "demon" that can take the form of the deceased, just like The First.
Imagine this scenario: sometime in the 1500s, the Watcher's Council becomes aware of a Hellmouth somewhere in the South Pacific. They attempt to defend the Hellmouth via traditional means (the dispatching of a slayer) but are unsuccessful in stopping the flow of demonic activity. So, in a last ditch effort to contain the Hellmouth, they invoke powerful magic, corking the Hellmouth with an island. A side effect of the spell is that the Hellmouth is now un-stuck in time and space, making direct travel to the island nearly impossible.
Before the Watchers could completely close the Hellmouth, one incredibly powerful demon -- the Black Smoke Monster -- escaped. However, he was trapped by the Council's spell. Upon discovering this, the Council dispatched a powerful warlock -- Jacob -- to keep the Smoke Demon in check and prevent him from re-opening the Hellmouth.
Imagine the post-"Lost" crossover possibilities. Jack and Angel have a brood-off. Sawyer and Spike team up to see whose "runner-up in love" story is better. Buffy and Kate share tips on how to keep two men pining for you long after they should have given up. Walt and Dawn swap "I was kidnapped by evil people" stories. Ben and Giles compare dark pasts and leadership abilities.
Again, I have ZERO belief that this is the actual "solution" to Lost (if there even is such a thing), but if this were to happen, I'd be in Nerd Heaven. Nerd-vana? The Garden of Nerd-en? Whatever. It'd be awesome.