I've seen nature and wildlife centers with multi-level hives behind glass walls, though no, I haven't seen a Langstroth hive with a glass side. You could do it, why not? Still, there's not a lot of action that happens on the outside frames. One of the attractions of an observation hive is you can find the queen, you can see her lay. In a 10 frame hive, the queen tends to lay in the middle four or five frames, and rarely on the edge frames.

Thanks. I'm thinking about ways to do it. I'd probably put a door to cover it.

I could watch bees all day, I think. It is fun to sit and watch them land/take off. This is our first year, and first two hives. Today they exibited the "washboard" movement at the entrance. Our book says this movement is not completely understood, but another sign of a well populated hive.

What an incredible idea---a window into the hive. Might help spot problems early. How about a plexiglas or Lucite hive? Just make the whole thing visible. On second thought, those plastics put off a smell when they get hot, I think. Bees probably wouldn't like it. But maybe they'd tolerate a bay window.