I tried using the 1" foam this winter with my hive. We have lots of scrap material at work, so I was able to wrap the hive completely around in the foam. I used rubber straps (Tie Downs) to how the foam in place, which worked out really well. The foam is a dark brown in color, so the color may help a little bit. The foam cells are small and closed, so it should be a fairly good insulator. I have a some entrance at the bottom of the hive, plus a smaller (1/4" x 1/4") hole under my top cover. This seems to give enough ventilation.
Let me know how you're foam insulated hive works out. It seem like a good idea. Thanks for posting the information.