My guess is you need to remove, perhaps among others:
gnome-session-flashback, gnome-session, nautilus, gnome-terminal,
gnome-control-center, gnome-panel, gnome-session-bin, metacity,
gnome-power-manager, gnome-screensaver, unity-settings-daemon.
What have I missed?
Try sudo apt-get purge gnome-session-flashback gnome-session nautilus
gnome-terminal gnome-control-center gnome-panel gnome-session-bin metacity
gnome-power-manager gnome-screensaver unity-settings-daemonIt will ask to
have the Trisquel metapackages removed but if I remember correctly none of
the preinstalled packages are set to auto (somebody please verify) so it
should be safe to remove the metapackages.