Perhaps something like www.workspot.com? Workspot uses Debian and provides access to a KDE desktop via vnc.Their setup seems to be pretty straight forward - the web form allows you to set all the vncserver parameters and then run the vncserver as your username.
Perhaps a web-based thin client system will be the easiest way for them to experience KDE/GNOME and test some of the applications in Linux. Anythoughts on building a simple web-based thin client test pilot?
