It's not really THAT rare is it? Unless i'm getting old, I think you can buy Amid... at The End. I definetely saw it at a record store around here about a week ago.
This is one of two people, Jim Harvey or Ron Reid. They were the engineers on this CD. The copy he is selling is NOT the Dark Symphonies re-release, but the original Avantgarde Version. It's rare, but not impossible to find, just long out of print.