"1. A cutout, particularly one in the photo you provided is going to have temps moderated for them due to heat from the house.
2. The cutout in the photo would actually *ALMOST* be more similar to a TBH with the bars perpendicular to the direction they run in current designs."

I agree on both points. The picture just illustrates that the bees will move horizontally and do not need much overhead space to survive.
The two lang sized (19" bar X 9 5/8" height) long hives that I over-wintered last year did great. Two out of two ain't bad, is it. (Some of my deeper bodied top bar hives didn't make it, though, so I'm not sure vertical movement is the problem.)