I saw a 3D printer at my son's elementary school computer lab just now--a $2000 machine, but what it turns out seems fairly rough. The shapes can be complex, but the surface isn't exactly fine enough for camera parts without some additional machining or hand finishing. I could see myself cranking out the slip-on lenscaps, though.

It has kind of a Heathkit or maybe COSMAC ELF look about it. I'm sure there will be something in 10 years that will make this thing look like a TRS-80 looks to us today-- http://store.makerbot.com/replicator.html