When Jay Leno replaced car parts, he could only print plastic moulds in 3D. Life's easier now, because moulds are unnecessary in the creation of custom desk kitsch and car parts as 3D printing got a stainless steel upgrade.
21 days and $US10 per square centimeter is all you need after you send a CAD design to Shapeways, a company who began offering 3D resin and plastic printing quite some time ago. There are specific size and detail guidelines to keep in mind due to models being printed in layers, but based on the moebius strip complete with moving parts, those guidelines can't be all that limiting. What's going to be your first 3D steel print? [Shapeways via PopSci via CrunchGear]