Personally, I'm interested in *making* one.
There are two types of analog reverbs: Spring and Plate.
Spring are easier and cheaper. You would be able to find one second hand cheaper than building one. I don't think they sound any good.
Plate reverbs sound much better, analog buffs claim they are superior to anything. They however, cost $5000 second hand. Building one would be cheaper, but seems hard. I'm thinking about it, but I'm only in the planning phase.
This is what I have figured out so far:
Sources of information:
Journal of the Audio Engineering Society, Vol.45, No. 9, 1997, p. 660-684:
Effect Design - Part 1: Reverberator and Other Filters
By Jon Dattorro.
This is part 1 of a three part article. If you have a decent signals and systems background already, this is a great reference! This part covers reverberator design (including a graphical plate reverb recipe) and various filters (cut, boost, low pass). The paper includes a pretty detailed analysis of filter topologies and noise, plus hardware issues. If you want to make high-quality filter designs, grab this article.
Audio Electronic, 1982
Supposedly has an article on plate reverbs.
Basic Construction:
Thin steel sheet 3’ X 6’(1/64” thin)
Enclosed in 8’ x 4’ frame
Internal pick-ups and driver.