Make has an excellent business idea involving SketchUp, woodwork projects, and entrepreneurial DIY stores:

Eventually you might be able to send off your files to a fabricator, lumber yard or whatever supplier – the stuff shows up, you make it! How cool will that be! Maker-aware suppliers could have all their parts/tools/things available as Sketchup components so we can use them to build our projects (and eventually order).

Why not take this concept and apply it pre-fab homes (within reason)? And perhaps there will soon be a day where you can download a car chassis, different interlocking component panels and then build your own “custom” car. I hear GM is in need of a new big idea…