Latest home experiment: cold-smoked 1.7 lbs of sockeye salmon. I followed Ruhlman and Polcyn's "Charcuterie" recipe for curing the salmon - coat salmon with salt and spice mixture, weight it, and fridge it for about 36 hours (I did 36 hours almost on the dot). Then rinse it well, place on a cooling rack in the fridge, uncovered, to let it air dry, 4 - 24 hours (I did it for 10 hours).
Then I rigged a cold smoking box. Took a small styrofoam cooler, and put ice cubes at the bottom. Took an empty food storage container (2 cups?) to use as a stand to keep the salmon above the ice, and placed the whole cured fillet on my toaster-oven rack, which I placed on the food-container stand. Popped a hole in 2 ends of the styrofoam cooler. I used a PolyScience Smoking gun with applewood chips, put the whole contraption on my stove top (so I could use the hood if things got too smoky - this was the first time I used the Smoking Gun, which was a Christmas gift). Blasted the salmon with 4 shots of smoke, once every hour for 4 hours. I'd open the back end hole so that displaced air could exit through there, rather than the smoke coming back out through the entry hole (trial and error).
Slid a cabled thermometer probe into the cooler - above the ice, about the same level as the salmon, not touching anything. Temperature varied from 52 to 54 degrees F every time I checked, which was about once every 30 minutes. Ruhlman and Polcyn say to cold smoke below 90F, so I was more than adequate.
Tried a little piece last night when I was done, and it both looked and tasted pretty good. Good smoky flavor. Maybe a little salty, but I'm OK with that as a first result. Consistency of the flesh was on target - still a firm flesh, silky in look and feel, like a smoked salmon should be. I'll have a larger portion tonight at dinner or Saturday morning for breakfast, but overall at this point, I'm very happy with how it turned out. It should be able to keep in the fridge for 2-3 weeks.
For things that don't need many hours of cold smoking, and for smaller items (up to a few pounds), this home rigged system seems to be a pretty good alternative to spending a few thousand on a cold smoker, yet being able to cold smoke foods, which is very different than hot smoking.
Not sure what I'll try next.