https://oceanwayaudio.com/as-the-sea-level-rises-for-immersi...
British (also available in consumer version and pretty finishing): ATC SCM150
https://atc.audio/hi-fi/loudspeakers/classic-series/scm150/
American: JBL M2 https://jblpro.com/products/m2
(Or just buy JBL commercial theater smaller models like many installers do)
German: Neumann KH420 https://en-de.neumann.com/kh-420
Yamaha NS-5000 https://europe.yamaha.com/en/products/audio_visual/speaker_s...
All these cost about thirty thousand dollars including appropriate amplification and tax before installation. I make this a loss leader run by all the industry for labor and materials only. Every one is a halo product and worthy of that description.