best used floorstanding speakers under 5k that has small footprint

Hi,

I am currently using a pair of ATC scm40 v1s and are looking for upgrade them. I love its mids presentation and I mainly listen to vocals and occasionally piano and cello (no orchestra).

My budget is $5000 for a pair of used floor standing speakers, might be able to stretch a bit based on specific cases. 

The ATC 40 v1 is still relatively small in footprint as a floor-standing speakers, I would like to keep this trend in my next speakers. 

Let me know if you have any recommendations. Thanks!

Yuheng