The shadow packages are just recently uploaded into the "unstable" directory
of our FTP archives. They are little tested, and I'm not sure that everything
has been shadow-ified that must be ("xdm" may be one of the programs yet to be
converted). You can try it now if you like to live dangerously. This will be
stable by the time we make the 1.2 release.
We are looking at PAM for the future, as that would allow us to support
multiple authentication methods.
Bruce