I guess I'm late to the party (what else is new?) but regarding the "glow map", what I've done in the past for, say, things like small lights in distant skyscrapers or on a starship or whatever else is create the texture map in photoshop, then, create a grayscale version and plug that into the incandescence slot. Then, you can use the alpha gain to control how "hot" the glow is. This won't illuminate the scene, though but it does work well for general effect.