Looking good. Will look awesome once you get some textures on it.
As for the Earth, check out Dean Scott's Earth tute (it's the best one I've seen)
http://personal.southern.edu/~dascot...nasa-earth.htm
As for the size --- make the earth down to scale rather than full size. You can fake the distance by simply scaling the Camera lens in LW so it shouldn't give you too many rounding errors. The only thing to ensure is that your satellite doesn't cast a shadow on the earth...