I hope I'm not too late with the response here, but I have a bit of personal experience that hopefully someone else can learn from. I did try using glowinc's paint on the base of a regular 55w automotive bulb.
It lasted less than a minute before filling the light assembly with black smoke. I didn't leave the power on long enough to see if it would burst into an open flame, but long enough to say it can't handle that amount of heat.