I was messing around with this and got some nice results (testing, so nothing post worthy) with glowing props.  But how could I make only portions of the texture glow?  For example a glowing flame paint job on a car.  I added an ambient node to my material, using an image map for the texture.  I tried blacking out and whiting out in a photo editor the part I don't want to glow, but it just overwrote the underlying texture.  Even tried making a png with the non-glowing part empty, but it just overwrote with white.