Back in the 60's I owned a guitar, Scandinavian in origin if I remember right, called a "Nashville Model 10" which had just the type of neck joint described above. It was a reasonable instrument, but I only owned it for about two years (I traded it for a more conventional, if more expensive, Gibson J45) so I can't speak for it's long-term stability.

I've never seen another since, but it goes to show that there is nothing much new in lutherie.