From a 2003 interview with scifi writer Jerry Pournelle (X)
Pournelle: Joss Whedon is very sharp. And he and I and [Larry] Niven very nearly came up with a fantasy series, which I would have loved to have worked on, based on the notion “Suppose the magic came back. We live in this world right now, and all of a sudden, the mana is coming back, and nobody knows how to use it, because we haven’t studied it in 15,000 years.” But some people have natural talent, and it will turn out, and we had this storyline that there have been some wizards all along for thousands of years. They mostly make their living doing prestidigitation. Stage magicians. And that was going to be one of our major characters, this 30-something-year-old witch who learned to be a stage magician but has far more talent than her mother did, so she gets it right more often, and meanwhile, the magic’s coming back ; we’re pumping oil out of the ground, we’re bringing up ores from deep under the Earth, you know, most of those things have mana attached to it. We very nearly made a deal with Joss on that one, and that would have been fun. That one I would like to have done.
What happened ?
Pournelle : I think he just got interested in something else, or didn’t have the financing, I don’t know. The trouble is I really wouldn’t want to work with very many people on something like that. We actually came up with a story treatment for it, at least a background for some characters. The general in charge of Fort Knox. Gold has an awful lot of mana in it, and suppose his daughter turns out to have a little bit of talent. [Chuckles] And he’s the general of Fort Knox, you see, with all these soldiers. That was going to be the pilot. You’re trying to steal the mana, but of course nobody knows there’s anything to steal, so, “Go after the gold. I don’t give a sh-t about the gold. I don’t want the damn gold, I want the mana.” [Laughs.]