Speakers and depth...

Anything with a "BBC Dip" and a warmer less defined bass will tend to give you a deeper soundstage. Upper midrange rolls off with distance and bass sounds less tight or crisp as you get further from the stage.

Rogers is a classic example but many follow the same design principles. Look for a speaker plot with a dip in the upper midrange and particularly a roll-off in the off axis response in the upper midrange (off axis response clues you in as to where instruments are - if it is in your room and close to you then the off axis response is very strong as you will well know if you play an instrument - if the sound is far away then the off axis will be even weaker or more attenuated - these are all clues that the source is far away giving the impression of a deeper soundstage)

Bobby,

Good point - as you figured out - I merged "distance" and "depth" in my comments .....how far something is away versus how "deep" is the perceived soundstage.

Thanks for clarifying and making my comments clearer. If I understand correctly - you are saying that a system that is designed to sound distant cannot give as deep a soundstage as it will tend to make all recordings sound distant. Did I get it?