This reminded me of Cory Doctorow's great story "Themepunks", which includes self-replicating 3-D printers. You can read it for free on Salon.com, but the links between the chapters are a bit broken, so here they are if you are interested:

http://dir.salon.com/story/tech/feature/2005/09/12/themepunk...

http://dir.salon.com/story/tech/feature/2005/09/19/themepunk...

http://dir.salon.com/story/tech/feature/2005/09/26/themepunk...

http://dir.salon.com/story/tech/feature/2005/10/03/themepunk...

http://dir.salon.com/story/tech/feature/2005/10/10/themepunk...

http://dir.salon.com/story/tech/feature/2005/10/17/themepunk...

http://dir.salon.com/story/tech/feature/2005/10/24/themepunk...

http://dir.salon.com/story/tech/feature/2005/10/31/themepunk...

http://dir.salon.com/story/tech/feature/2005/11/07/themepunk...

http://dir.salon.com/story/tech/feature/2005/11/14/themepunk...