Actually, there is a Yahoo group for Concept gear at
http://groups.yahoo.com/group/conceptaudio/
It is run by Chris (vintagestereo) a fellow AK'er.
Check it out. It's a small group but contains some
useful info about the various gear sold through
Pacific Stereo in the 70's and 80's. I think it is
more rare than collectable but I guess that makes it
collectable in itself. There is a nice example of a
Concept 2QD listed for sale over on
www.audio.net
for $149 w/ cartridge. Grab it if it's still there. Jon