The folks at RepRapCentral have just printed what appears to be an entire DSLR system on their MakerBot Replicator. This startling print by Sergey includes the camera body and a permanently attached zoom lens.
However, closer inspection shows that there is no optical lenses in the print, as one would expect.
Nevertheless, as RepRapCentral states, it's a "Glimpse of the Future". Someday we may indeed be able to print functional objects as represented here. Peter from RepRapCentral says:
It won't be too long before 3D Printers can prints optics and dial in certain characteristics. The electronics will be 3D printed, so its not beyond the bounds of possibility. Its going to happen, its just a case of when.