I too have been watching these come and go! I think I need a set of electrostatics, though I sort of want full range. I always thought that the mid-bass/bass clarity of the old Koss, acoustats thru the panels was unrivaled by any of the cone drivers of the time.
Does anyone remember the Koss reverse electrostaic hybrids of the 70s? Used panels for the base/midbase and a dome tweeter at the top. I remember these being great sounding speakers, electrostatics with a wide sweet spot.