Shapeways is a 3D printing webshop. They offer prints in non-plastic materials such as metals, ceramics, glass, coloured sandstone – but also plastic, of course. The shop is run using professional grade 3D printers, so the results can be expected to be of higher quality than if you self-print with a RepRap or similar device.
The beautiful thing about the site is that it accepts STL files. This means that you can use the same designs as you do for your RepRap here. For instance, you can prototype parts in plastic and then have the final design printed in steel, glass or even silver and gold.