I still have cold induced flickering with leds on a couple of units. I didn't have a non-responding unit tonight though. I believe that it is the 3.3v regulator close to the 0c temp specs. 2 7w c7 bulbs inside the enclosure seems to be working pretty well. I just tried this tonight.
I'll try and get pictures tomorrow. Basically it is 2 bulbs, and I use the clips on the socket to attach them to a paint stirrer, cut to fit snugly, that is wedged vertically in the case above the transformer. It warmed the case up, and the flickering went away after about 10 minutes. The show was still flicker free after about 2 hours with the lights on.