We bumped into a comprehensive list of 3D printers, and a detailed chart comparing all currently available 3D printing options costing less than USD$20,000. The chart is prepared by Castle Island, who offer a paid newsletter, "The Additive Fabrication Spy" (USD$199/yr) covering in detail the 3D print industry.
The printers covered include the Do-It-Yourself variety (MakerBot, Fab@Home, RapMan, RepRap) as well as the well known commercial makers (Dimension, Z Corp, 3DS and Solido). Desktop Factory appears, but as we all know, they've shut down for a while.
Via Castle Island