Chemtube3D now has available 3D printable transition states for selected reactions in both the .stl and .x3d format which work with most printers. A list of available transition states is shown below:
The models shown above were printed using Shapeways.com. The coloured model on the left was printed using the "Full color Sandstone" material, while the white model on the right was printed using "White Strong and flexible plastic".
3D hubs is another website that provides 3D printing services. The website is a platform that facilitates transactions between 3D printer owners and people who need something printed.