MMDR Designs, run by a husband-and-wife team, has recently taken off from at-home fun designs for acquaintances to become an official business. David Rosenfeld, one of the owners, long ago designed a pocket knife to be created with traditional manufacturing means. After that method didn't produce the intended product, he redesigned it in 3D using Alibre (now Geomagic Design), and has successfully 3D printed a folding pocket knife. Check out the background and details in the full article: http://3dprint.com/33754/3d-printed-knife-2/ ‎
Below is a photo of Rosenfeld's 3D printed pocket knife: