Steve,
The reason you couldn't find "The Gaslight Tapes" from a legit source is that it is a bootleg. A retailer that wants to maintain a relationship with legitimate record companies does not sell bootlegs.
If you check out the rec.music.dylan group, you'll see a lot of buying and selling of such boots.
Rick,
I'm surprised that you're allowed to play bootlegs on your station. I had a radio show in college, back in the days of L.P.s and playing bootlegs was strictly forbidden then. No matter their musical worth.
Jerry