Daniel-
We can use Erik's idea for adding neat features to the Brilliant prose page as a start. Then that page can act as a queue for articles that Nupedia can take-up and then put through a simplified Nupedia polishing process by area experts. The Sifter software can be used to make this easy but it is not really needed.
Well, here's the thing. Our Main Page is protected. Our Main Page links to the Brilliant Prose page, which would also be protected. The Brilliant Prose page would only link to verified revisions of articles. A user can choose this path
Main Page->Brilliant prose->Article
And they will never see an "unstable" article -- these pages would always be in a reasonable state. It is the same thing as a separate site, but happens entirely within Wikipedia. We might have to streamline the whole process -- turn BP into a directory of pages, make this directory part of the start page, and warn readers that pages linked from pages within that directory may not necessarily be in as good quality. This would not preclude us from also using a category system that contains *all* Wikipedia pages, not just filtered ones. On the other hand, we would retain wikiness and encourage people to also browse and participate in our unstable sections. I think that's a good thing.
Of course the BP articles could be taken as they are and copied to another site, but that would not really be very useful. What might be useful, if BP grows into a directory of sorts instead of just a single page, and if there would be lots of articles linked from there, is to publish only these articles on a CD-ROM, in print etc.
Regards,
Erik