Some of the rubber powered kits say that they can be converted to glow and give instructions on how to do it. The ones that I have seen take a very small engine like a Cox .010 or .020. Since this is in the R/C section, I assume that you want to convert one of the kits to R/C. The problem there is going to be the micro components that you will need.

If you use a heat-shrink covering, you are going to create some real problems. First of all, you will add weight. The main problem is that you will crush the structure when you try to shrink it. Stick to the tissue covering and dope it on. I wouldn't even paint it but make sure that everything is completely sealed with clear butyrate dope.