Wowwee!
It seems the one thing I've heard Beekeepers disagree about the most are the mechanisms of heat! Everyone gives conflicting information about how bees stay warm, and now about how they stay cool.
Bees are tropical by their nature. Same as other highly successful lifeforms, they've developed an adaptation that allows them to survive in more varied environments around them. Honeybees in Asia place their combs on open branches, keeping the temperature by covering it. Mellifera and Cerana have taken to building inside cavities.
The reason for this, I'm sure, is as protection from predation rather than as a temperature control. If temperature were that important, the Dorsata and Florea would have died out a long time ago. Still, nesting in cavities allows them to manipulate the environment to some degree. This isn't adapting the environment as Humans would, I.E. donning a "winter coat," if you will, rather than building a cabin.
Tropical varieties of Mellifera tend to find any cavity to shack up in, while the Temperate varieties will invariably look for hollow trees. I hypothesise a living tree is a more controlled space than holes in the ground, or free hanging comb.
Trees transpire. This helps to keep them in a temperature range. The leaves shade the trunk and limbs so that the sun doesn't increase temperature until there's an absence, allowing the sun in to warm the dark colored bark. The fact that Mellifera will build open combs in extreme environments is a testament to their heritage, not to their hardiness.
Humans built the "wooden box." They've also built straw boxes, clay boxes, cow dung boxes, cement boxes, and glass boxes. Wood just seems to be the easiest and cheapest method. Problem is not re-inventing the bee, it's re-inventing the tree!