This area has links to related work at other sites.
OpenAFS
In February 2006 there was an email thread on writing an AFS aware WebDAV server. The head of the thread can be found at http://www.openafs.org/pipermail/openafs-devel/2006-February/013502.html.
Filedrawers
As of 2005, UMich's mfile service (based on filedrawers) doesn't use WebDAV, but instead offers a web-application based interface to interact with AFS. We've written a utility called waklog (web aklog) which acquires the user's credentials, and allows us to manage that user's filespace. The filedrawers UI demo can be found at http://filedrawers.org/filedrawers_demo.php. More information about the project can be found at http://www.filedrawers.org/. Willie Northwayat UMich is one potential source of information about ths project.
waklog
Presentation on accessing AFS through the web using Waklog - http://www.modwaklog.org/afs_workshop_2006/
mod_waklog - http://www.modwaklog.org/
WebDAV + Apache + AFS
Mailthread from the DAV-dev list http://www.lyra.org/pipermail/dav-dev/2005-June/006006.html