PluggableUserFolder is a Zope user folder that is designed to be extensible in all ways. It supports extending via "plugins" to add support both for ways of identifying the users, such as using cookies instead of Basic HTTP Authentication, and adding new sources of users, such as LDAP or SQL sources, and also extending the role management, such as group support and black lists.
It also supports using all of these simoultaneously. You can have users defined in Zope, in an SQL database and via LDAP, all at once. You can have groups and blacklists at the same time. You can support both cookies and SSL Certificates without problems.
There is now a cps-devel Mailing list for CPS3 (and CPS2) developers, as well as for other products developped by Nuxeo.
CPS users lists (cps-users (english) and cps-users-fr (french)) are also available.