(like I really needed a seventh pair!?)
The EPI Model 180!
Like stacked model 100's, this model has better bass, and higher sensitivity. While not of the same vintage as the 500c, at circa 1974 or there abouts, this pair should do nicely in my new "vintage" system.
http://gallery.audioreview.com/showphoto.php?photo=6876
I'm going to do the surrounds next weekend.