As referenced in the inevitable earth render image, this is the evolution. I took the Nasa textures and changed them completely smoothing the continents and creating a driver for a front/backfacing material with transparent oceans to set a 3d earth against an artificial background. This is for animation purposes rather than stills (for stills I recommend to not make the ocean transparent). But the depth only is apperant during the animation (which has to be very slow). I already did some test renders for this animation but I am not yet satisfied with the results. So still some way to go.
