Hi all,
in the past year the Human-Computer Interaction Lab of the University of Udine, Italy, has developed a visual editor (and a viewer) for virtual exhibitions, called VEX-CMS, based on Ogre for 3D graphics and wxWidgets for 2D GUI elements.
The editor allows a curator with minimal technical knowledge to assemble a virtual exhibition (e.g. of artworks), and design tours for virtual visitors.
If you're interested, you can download a demo the software at http://hcilab.uniud.it/vex
and/or see the youtube video
HCI-Lab, University of Udine