I didn't think posting in this old thread would be appropriate so I thought I'd bring the discussion back to a new thread.
Here's the link to the old thread and discussion:
http://forum.sausagemaking.org/viewtopic.php?f=9&t=3185&hilit=cold+smoke+generator&start=255
It makes for a great read, but unfortunately, none of the image links are still active. I have some 4" Al pipe I want to play around with to see how well these work as cold smokers. Does anyone that posted in the original thread still use this?
Here's another link to another site with a nice homemade coldsmoke generator:
http://www.smokingmeatforums.com/t/142875/smoker-in-a-building#post_999805
He even incorporated a smoke purge fan to empty out his smokehouse so he can open the door. My smokehouse is in my basement so I would probably do the same.