If you have the room and access to someone else's junk, they are pretty easy to make by gutting and modifying an old fridge. My dad has been using his for years and it is incredible.
Yes, they
ARE! I've been using these for 3 decades and more, they Work & Work
WELL! You
MUST however find one of the older model
GLASS Insulated versions. The newer ones are Foam insulated, and will leach
FORMALDEHYDE when heated!!
Here's a picture of the one I've used for the past 6 or 7 years:
Literally Hundreds of pounds of fish, sausage and so much more run through this one.
The unit on the left is a Centro model, which I use for a firebox when cold smoking. Smoke passes through the flex tube to the main fridge unit and can be operated when ambient temperatures are not all that favorable by running the flex tube through a tub of salt ice. The Centro works FINE as a stand-alone smoker, and uses regular chips rather than expensive pucks. The fridge of course is
Deadly as a hot-smoker as well.
Recently gave the fridge to a Buddy as I have acquired a new unit to work with. It is one of the old-style hospital food warmers, 3" of insulation, all stainless, 400 pounds on wheels. Will put a picture or two of the latest up once I've got her running...
Cheers,
Nog