I have listed some links below of high efficiency speakers, most of which the manufactures are very transparent regarding components used and cabinet construction.
https://www.coherentspeakers.net/#!
https://www.atelier13-usa.com/coherent-audio-loudspeakers
https://www.vaughnloudspeakers.com/
http://www.coincidentspeaker.com/super-victory-III.html
https://www.coherentspeakers.net/#!
https://www.atelier13-usa.com/coherent-audio-loudspeakers
https://www.vaughnloudspeakers.com/
http://www.coincidentspeaker.com/super-victory-III.html