Short of dropping fair use materials altogether, we could clearly label the fair use status of images on the image description page, maybe even saying "This image is *not* under GFDL, it was copied from ... under the fair-use doctrine." And our [[Wikipedia:Copyrights]] should then contain a notice that for the license of images, the description page ought to be checked.
[[Wikipedia:Copyrights]] would also need to have a notice that whenever we quote Dr. X in our biography of Churchill, that the quotation is also not covered under the GFDL. I certainly hope that it never has to come to that!
-- Toby