From the beginning these products have been in high demand. With the average audiophile's tendency to move on to other equipment no matter what, some norh products definitely change hands. I do not see a lot of them available on the web, but I have bought a few items quickly and "quietly" so I imagine that is how it often happens.
Probably the 3.0 speakers are the most available (these went like hotcakes at one of the audio shows) used items, and the CD-1 and Marble 9 and 4 models are some of the least available.
There were not a large quantity of these products made (CD-1 and ACA) and with the great value for price, they just don't change hands that often. They are very hard to replace for anywhere near what they cost.
To make matters worse, damaged equipment has been available and new owners may not realize what they are getting. It is probably best to try to track down the chain of ownership if possible - it should not be too hard with this gear as many original owners are right here on this forum.
