Yes, I'm aware
of terragen and it's potential, haven't really used version 2 though. I prefer to paint these days. Anyway, there's not really a need for planetary scenes, even from high orbit.
I can see it beeing used for various cinematics, but that's extremely low priority polishing work, which doesn't become a focus until 0.9.
edit: Something else just occurred to me. Could you perhaps render images similar to satellite photos? Terrain images from top down?
Here are some reference images, ask if you need more. It's important, that the light source direction is not obvious. It has to look flat, as if the light is right behind the satellite and not to the right or left. Also, no clouds please, we need them on a separate layer. Would be great if terragen could render these as well.