Examples of (G)UI backend...?

Does somebody know existing designs or code for the following?

we want to put a GUI on top of one or more robot controllers. The GUI
is a "dummy" front on a more intelligent backend ("server") that can
connect to the different controllers, display their data and accept
commands from the GUI to control them, _and_ that allows to store
reported data to a database for later analysis and report building.
(The rrd database <http://people.ee.ethz.ch/~oetiker/webtools/rrdtool/>
 seems promising for this latter purpose...)
Moreover, we want the same backend server to be useable from a
compiled GUI as well as from an applet based browser GUI.

I think I've seen many of the requested parts in some presentations
during the Linux in Control meeting of last May, but I think I haven't
seen the whole backend-based system...

The primary use of the backend would be for "small scale" systems,
i.e., with at most a couple of dozen signals. _Not_ massive data
acquisition systems with Gigabytes of generated data per second.

Suggestions are welcome :-)

Herman

-- 
  K.U.Leuven, Mechanical Engineering, Robotics Research Group
<http://people.mech.kuleuven.ac.be/~bruyninc> Tel: +32 16 322480