When I was in charge of Wharfedale's R&D and product development, we most definitely used ABX. Speakers behind an acoustic curtain the entire width of the listening room. You had no idea what was behind there. You just had a switch box and a sheet to write your comments. It was always fascinating to find out what my devious team had put behind the curtain! Actually in practice it was often used to optimise crossovers and cabinet construction details. Almost always a mono test to prevent confusion with listening to stereo.
An ABX test, I have to say is very difficult to do in practice as a test subject!
Regarding speakers, I use the LX521, designed by the ex-Hewlett Packard spectrum analyzer developer Siegfried Linkwitz. Based on hard technology
http://www.linkwitzlab.com/ .
Craig