It would be difficult (impossible?) to do, but what about creating a movie of the graphic novel The Origin? It's basically the movie with Sarah Michelle Gellar replacing Kristy Swanson and supposedly ties in with the series the way it was originally intended. I've seen parts of it (I need to find a copy for myself) online and it seems to fix the inconsistancies. For instance, the introduction of Merrick and Buffy is the same as the episode Becomming, Part 1 ("I'm destiny free, really.") and the school burns down at the end. I assume other things match up too, such as Buffy being a freshman instead of a senior.