Paul:
If you patch ConsoleKit and GDM with the following patches, you can try out the code that adds such support. https://bugs.freedesktop.org/show_bug.cgi?id=19333 http://bugzilla.gnome.org/show_bug.cgi?id=536355Do you expect these patches will be merged into GDM 2.28?
I hope so. The patches are still in review, and may take some time to get upstream. Until the review process is done, it's hard to say which version of GDM will support multi-display. Brian