I don't have a drum yet (build is in the works), but I do have a WSM that I cooked on during a snowstorm on Dec 23rd in 26 degree weather. The wind was what was killing me that day., not the temps. I wound up wrapping the smoker in a moving blanket, and keeping the vents open. It worked great. At smoking temps, it really doesn't get hot enough to burn the blanket. I imagine a drum would be similar.
I would stay away from anything that contains fiberglass unless it is completely contained.
WSM, Weber Genesis Silver-B
Weber Q Portable
1956 Weber 22 1/2" Bar-B-Que Kettle
and a Super Fast R E D Thermopen!!!