I have posted at http://academiccopyright.typepad.com some thoughts on the availability of copyright information and archival materials -- three different models. I am still having trouble on this blog getting materials to save and publish. Sorry for sending everyone to a different blog.
The jist - three different models - one where the archive has copyright everything they could unpublished, and so the materials remain under copyright until 2048; another (Library of Congress) that gives c info on each collection (lovely); and a traditional (non-digital) archive that is no help whatsoever on c.