Comment 4 for bug 449198

I have 3 suggestions for implementing this:

1) In gnome-appearance-properties:
   [x] Aply this theme to the login screen (displayed/enabled only if the user has admin rights)

2) In gdmsetup:
   [x] Apply the following theme to the login screen: [Current | v ]
        [x] Use the following custom background: [/path/to/image [ Choose... ]]

3) In gdmsetup or as a separate entry in System > Administration:
  [Change look of login screen] --> that button would run $gksu -u gdm dbus-launch gnome-appearance-properties, and add something like a notice or window title to differentiate the dialog from System > Preferences > Appearance)