Cool. Definately looks like you could render out some heavy surface detail (what do the movie space-ship modellers call it? Cruft?) and then cut-and-paste a bunch on to a new document, and apply that to your less-than-detailed hull. I imagine after a while you could even start to think in 3-color space. Painting the stuff by hand would be very difficult, though! The thing that really gives it away is the lack of cast shadows. And edges, of course -- same as bump maps.