Last year I built a cold smoker from scratch even though I have no construction talents. I couln't find any plans on the net at all so I drew up what I thought would work and adjusted things as I progressed. The only power tools I own are a miter saw and a drill. I'm pretty proud of the way it turned out.
I use the A-MAZ-N tube smoker on a patio stone for smoke. So far I've cold smoked turkey legs, fish, chicken, ribs, bacon, eggs, salt, pepper, and cheese. I have bought a hot plate for it but haven't tried it out yet beause I want a fancy thermometer and the wife hasn't released funds yet.
Last week I did a rack of ribs by cold smoking the ribs for 3 hours before doing the rub. They were fantastic even though my BBQ is just a "cheapo". I adopted a secret process that a friend of mine who has a big green egg uses. (I'll share if anyone is interested.)