Just came across an article on Wired about the Wachowski Bros who are notoriously secretive. Written in 2003, it doesn’t talk about the Sophia Stewart stuff, but it does have a few interesting details about them. Probably the most comes right at the beginning:

If anything, the Wachowski brothers have become more reclusive since the first Matrix came out in 1999. They haven’t given an interview in four years, and under an unusual deal with Warner Bros., they never have to talk to the press. Anyone who works on a film with them is made to sign a nondisclosure agreement. “They just want to stay as incognito as possible,” says their manager, Lawrence Mattis. When I told him I was writing a story, he chuckled: “Good luck going down the rabbit hole. There’s no map.”