Yes, there's RepRap and Fab@Home, but it's also possible to just get down and do the whole thing yourself too. Not everyone would be able or interested to do such a thing, but certainly everyone enjoys a good story. Alvaro Fogassa is publishing an episodic story of how he's trying to build a 3D printer out of "standard tools and off the shelf hardware". In fact, his base will be a run-of-the-mill Lexmark Z12 inkjet 2D printer. As this is a part-time venture for him, you will see updates only periodically; he has the same problem as the rest of us - not enough time.
Via Homemade 3D Printer