A rewrite of GDM is underway. On 15 October 2007, the new design replaced the existing SVN trunk.
At the moment, this rewrite provides a functional login program, but is missing some features which are in the last stable (2.20) branch. It would be great if more people could get involved to help complete the rewrite.
The existing stable branch will continue to be maintained with bug fixes until the rewrite is ready. Apologies for any inconveniences this causes while we are working on this rewrite.