Interesting topic, twl. I would like to hear a speaker like yours to better understand what you are talking about.
At last year's Home Entertainment show, I spent quite a bit of time listening to the Roman Audio speakers, which use the Diaural crossover. I felt there was a seamlessness and overall "rightness" about the sound that was different from most other things I had heard. The Diaural is a very simple crossover, and I wonder if what I heard is along the lines of what you are talking about.
At last year's Home Entertainment show, I spent quite a bit of time listening to the Roman Audio speakers, which use the Diaural crossover. I felt there was a seamlessness and overall "rightness" about the sound that was different from most other things I had heard. The Diaural is a very simple crossover, and I wonder if what I heard is along the lines of what you are talking about.