The best speaker for a small room...at any price point.

Don't underestimate what room treatment can do for sound quality. IMHO that can improve the performance of almost any (if not any) high end system. It's not that they sound bad before, just better after. 

... hard to find but well worth it: JBL L25 PRIMA (funky cabinets, but considered by some former JBL designers as one of, if not their best, truly successful-sounding speaker designs

@jayh31 In my current 12x11x9 space, 

https://systems.audiogon.com/systems/7605

I needed acoustic treatments to make the very small KEF LS50's sound their best. Without the treatments I was getting a headache listening to these small speakers at moderate to low volumes. Now it sounds great without fatigue.
 

The Wilson Beseech Discovery's would be my choice. Super fast and deep bass due to carbon fiber cabinet which nearly eliminates cabinet resonance.