I checked the google 3D warehouse and found many interesting models including domes, polyhedrons, buckyballs. I am wondering the possibility of creating either the arbitrary sp2 carbon structures or more challangingly the beaded models with the google sketchup, which seems to be a very good free software for the 3D CAD.
The figure below shows a few sample objects I found from the 3D warehouse.
Personally, I found the polyhedral dome in the upper right corner interesting. It would be interesting if we can build toroidal-shaped dome. Additionally, the google sketchup seems to provide the best free software for us to play with the idea of public arts.