Nicko, did you buy a smoker?
I came up with this idea driving down to Florida two weeks ago. I'm thinking of making a cold smoker, using an old but working refrigerator as a temperature-controlled smoke chamber. The plan is to drill a hole in the top and another one in the side, toward the bottom.
Next, take an old stainless pot with a tight-fitting lid you won't be needing any more. Have your local metal shop attach a fitting so you can put on a flared copper tube probably about 10'. The tube should be long enough to wind into a coil a little smaller in diameter than the lid, , have them flare it at one end. Attach the coil to the lid, bending the coil as necessary to allow it to sit on top and rise from it, to allow for cooling of the smoke. Now, run a plastic tube from the pot lid to the bottom hole in the refrigerator, and another one from the top hole to the outside, so you don't fill up your house with smoke.
Put your smoke generator (pot) on a burner or hotplate, put in hardwood shavings, whatever you want to use for smoke. Turn up the heat until you start to get smoke. Put your meat or fish on the rack in the smoke chamber.
If the copper coil gets a little warm, it's ok, but you don't want it to get so hot you melt your plastic tubing. If it does get hot, a fan might cool it, otherwise you would need to arrange for water cooling. The cooling coil would probably need to hang into a kettle of cold water.
I haven't done this yet myself, so if you succeed, you may consider yourself an engineer as well.