Most impressive small footprint speaker

WaveTouch Audio Grand Teton or Antero - the equal of the best out there at a bargain price.

Proac Response D2 - truly magical / majestic / holographic sound with the right tube amplifier (e.g. Line Magnetic 518ia, etc.).

Legacy Audio Calibre - phenomenal resolution, sound quality and soundstage.

Gamut RS3i - as good as it gets... but... at a price.

Any of these when coupled with the right electronics will equal or beat any of those offered by AudioTroy

Do you have an "unlimited budget?"  If not what is the purpose of this exercise?  Regardless "most impressive" is a personal judgement. 

Dynaudio Special One

+1 Spendor. I choose the A7 over the D9. 

Magico A3
Paradigm Persona 3F
Vivid Kaya 45

I could live with any of the 3 floor standers (almost full range) listed above.

I have not heard the Focal Kanta 2