The screenshot above shows Xfce compiled on a PureDarwin 9 system from MacPorts, using xfce4_axiom_theme and a background from psdgraphics.com.
Xfce can be launched so that it can be accessed by VNC clients.
Note: currently this appears to work only as the root user, needs to be investigated.
sudo Xvnc :0 -desktop X -alwaysshared -httpd /opt/local/share/vnc/classes \
-geometry 800x600 -depth 24 -rfbwait 120000 \
-rfbauth /var/root/.vnc/passwd -rfbport 5900 &
sudo launchctl load -w /Library/LaunchAgents/org.freedesktop.dbus-session.plist
To be continued.
Thanks Anders F Björklund for his continuing support and bugfixes of Xfce in MacPorts.