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

Joseph Audio Pulsar2 Graphene. 

https://www.lansche-audio.com/products/s-series/no-4-2/

About 12 years ago, I had used Lansche 4.1 (pre model of 4.2) at a room of 12ft wide and 10 ft deep room driven by Silbatone 300B 8W SET amp fitted with Nos WE 300B made in 1940’s.

The sound was excellent with pristine treble out of plasma tweeter, deep and tight bass out of active woofer despite the small room.

This will be best  cost no object option.

Agree with the Raidho suggestion (or Borresen if you can swing the funds). Consider the D1 or possible even D2 if it's a dedicated room. Nice thing about Raidhos is they're designed to be placed wide apart and close to side walls (though they need 3+ feet from front wall). They're amazing speakers with a glorious tweeter. Smaller Vivids are also quite nice in a smaller room.
I moved from a large room with full range Peak Consults (and subs) to a smaller 13'x16' room. Both my Raidho D2 and Vivid 1.5 sound great in this room. Bass is solid and tight to 40Hz. On some music I miss the extended bass I was used to, but for most music it isn't an issue (either that, or I've adjusted). Room treatments and bass traps can be a great help if it's a dedicated room. 

Other possibilities: Though not at the same sound level as Raidhos and Vivids, the Larson speakers work up against the front wall and work well with room modes. I heard them at a dealer and was impressed. I'd also consider Kii standpoints--their DSP evens out the bass response and goes quite low. Haven't heard them but would like to...

Value: Fritz Carrera BE.

All-out: Gamut RS3i.