>In Canada, Tegart Apiaries have devised a five-frame nuc box... It has
hard plastic contact and lid surfaces and is stryo filled.

Better Bee here in the U.S. sells them. They even look like picnic coolers.
The top cover fits snugly and there is only one hole, about 1 inch, in the
front of the box which is about a quarter of the way off the bottom. The
opening, besides serving as an entrance, also is used for feeding. Syrup
can be quickly pumped into the nuc through the opening.  Since the entire
inside is hard plastic, bees feed from the syrup at the bottom of the nuc.
Since there is only the one opening at the front, the inside skin is hard
plastic, and the cover fits tightly it does seem to me there would be
problems with condensation, though. Yes? No?

Regards,
Dick Allen