JT,

Could you elaborate alittle more about using Carrara ERC? This is an interesting shading/lighting problem, I would love to know how to somethings like this up.

In theory, this effect could be achieved if the glow channel could be controlled by the invertef highlight appearance, correct? Or am I thinking about it in completely wrong terms?

Another option,perhaps, would be to have a sphere of lights hooked to the sun (parented to it) with negative ones around the sun and positive ones directly opposite the sun (2 half-sphere replicators with thicker distribution in dome centers). Then have lights in both spheres only affect the highlight of the light-on-earth shader (with shininess set to zero and highlight to something bright and light)... Would that work?

I am in a middle of a project and can't test my theory :(.