"What's The Best Value Speaker In $5k-$10k Range?"

PSB Synchrony One

I am rephrasing your question to:
Given my room size & gear-esp amp, what is the smartest move up in speakers to give me world class performance, reveal the benefits of any other upgrades I make and provides "tremendous value?"
Revel Salon 1.for ~$5000. Well below your budget ceiling.
You now have money for some power conditioning and perhaps some better i/c's and speaker cables. These will also give you the best bang for the buck if you buy wisely. I am sure many will share some thought on those, myself included. Cheers!

I'd suggest at least auditioning some Merlins in that price range.

The Revel Studio speakers are very good, especially for the money. (I
owned them for about five years, and sold them for about $4,500 a few
years ago.). They do everything very well, although to be honest they are
not truly great in any one area. The salons are very similar but with even
deeper base response, (and in this category they do achieve great bass
response). The Studios, and especially the Salons, need a fair amount of
power. (I used a 100 wpc amp and that was not enough power so I
upgraded to 200 wpc amplifiers. That was with the Studios and I've heard
the Salons need double that.)

I upgraded to the Eggleston Andra II speakers a few years ago. They truly
are an upgrade in all aspects. The treble response is much more refined.
The bass response is deeper than the Studio, (and as good as the Salon).
They are more transparent than the Studios and they completely disappear
from the soundstage. The imaging is about as good as I have ever heard.
100 wpc amps will work but 200 wpc works better. Used they run around
$8-9K.

My two cents worth.
Good luck in your search.

In answer to your original question; I'd suggest Dunlavy SC VI's. Now regarding your 20 X 20 room; that's a whole 'nother challenge.