Your post (question) sounds like a fishing expedition to me. Particularly the "If one had a budget of $20K max". Not being snarky.
My advice is to get a map and spend a good while, days at least, and mark all the audio stores that are within striking distance by car. Exhaust those stores and then go flying to get to the next level.
The best advice above is to go to the Florida show, which includes another great piece from above. Spend $1k on your search and $19K on speakers.
Regards,
barts