10k Towers with biggest soundstage?

IME, soundstage reproduction is largely dependent on both the speakers’ power response uniformity and the room’s effect on it. Early reflections can muddle the best speakers’ and lack thereof can make lesser ones seem better. Some speakers will give better results in particular situations than others depending on the size shape and their placement in the room.  You can get a near ideal objective performer like Revel F228 Be ($11K) but you still need to avoid early reflections, create the proper symmetrical triangle for the sweet seat, etc. A good preamp helps too. 

Crusty is spot on. You just can't tell by listening in some other room, other than their potential to perform, or not.

I agree with Danager.

 I have the GR-Research NX-Oticas, one step down from the NX-Tremes  and the soundstage is 10 feet deep behind the speakers and at least 3’ beyond the outside edges of the speakers.
 

These are open baffle speakers so somewhat like Maggie’s, only easy to drive.

 I have heard the NX-Tremes, and they have a somewhat larger soundstage, but they are very tall.  Low wife acceptance factor.

Watt Puppy’s would be (and is) my choice. When properly setup, they throw a large and extremely realistic soundstage