There are a few people around the world who actually have a domestic room that can accomodate a triple stacked set (or more) of the original Quad electrostatic. This makes each stack nearly 2.4 metres (8 feet high). In due course, more photos will be added to this page of triple stacked Quad projects found in various countries. As a general rule, this is a very expensive exercise, not just because you have to find, and probably rebuild 6 original Quads, but then you have to work out how you would like to amplify them. Will you use 4 or 6 mono amps, and a complicated pre-amp feed? Will you wire the speakers in series/parallel to obtain a reasonable impeadance at high frequencies? The list goes on.
Here is our first set of tri-stacked Quads. The owner does not want details published here.
Here's a recently built set of Triple Quad ESLs that's found a home in the West Indies. Apparently, the owner is an amplifier manufacturer, we're not saying who, so the "problem" of enough amps to go around probably doesn't hold in this case - go for 6 mono amps and be done with it, I say!
This magnificent construction, and pictures, courtesy of Wayne Piquet, (R.I.P.) Florida. (Click to enlarge images)