My friend Tony builds the most amazing contraptions from junked copiers and printers. When I made him aware of the RepRap project, he pulled out all the stops, and built himself a RepStrap, with his own extruder design. All the parts, from the five linear slides, to the touch screen monitor are from salvaged office equipment. Don't judge performance by the print quality, as he's only been at it for a few days, but I can say that the extruder works well (especially since he's using
my hot end design).
Enjoy.