What would your dream build be like? Would love to hear new interesting designs

As the title suggests I would love to hear your wildest design ideas or what you’re dream build would look like. Cost and space no object.

I personally would love to build a 3 way horn system with 15“ bass, 2“ or 1,4“ mid and 1“ tweeter..
maybe even build a horn reflex enclosure for the bass..

phase aligned and only first order crossover passive to achieve (almost) phase linearity e.g. close to zero group delay over from 100hz upwards.

Efficiency should be 97db or more…

enclosure volume would be between 300 to 500 liters. (10 cu.ft. - 17 cu.ft.)

Crossover points would be about 500hz and maybe 2.5khz for 2“ driver or 5khz for 1,4“

I love a very accurate and real soundstage so phase linearity would be one of the many factors I would focus on.

Also maybe bi-amped with low power tube amp in the mid-highs and solid state in the bass.. but still fully passive.

Would love to hear your ideas!!!