I blendered up the above gearbox and posted it, and although nobody's printed it out on their 3D printer yet (only a few users and the MakerBot team have 3D printers at the moment) I've validated that the pieces are manifold (i.e. solid) and printable on a no-support-material 3D printer.
One thing I noticed is that the set of Blender skills needed for solid modeling is fairly different from that of making viable 3D art. Perhaps the biggest difference is that, in the world of solid modeling for 3D printing, there is NO SUCH THING AS LIGHTING.
With many of the lessons in a typical 3D training regimen being mostly useless to a modeler interested in making solid parts, and with many otherwise obscure techniques popping to the foreground, I'm wondering if there aren't some tutorials I can be linking people to which focus on solid geometry.
Anyone got links?