I think you'd get even quicker results with 'RTE' on this render, Lane. There is pretty much no ground visible so that wouldn't be a problem, you also wouldn't have to wait on the sky and ground rendering first before all the objects were rendered. It would do it all in one pass.
You could also drop the atmospheric sampling if you used RTE, there is normally very little noise with RTE and about 32 samples, maybe even less would do. I'd imagine you had used significantly higher samples for the first image to reduce atmo grain as it's very smooth.
Cool, definitely your style! I like the X-Files/UFO idea, too.