Hi Ben
As simplebbq said, cold smokers are easy to build!
My 1st one was made out of an old Cider cask, some SS tube leading into guttering pipe, that entered an old stripped down oven with 2 racks.
Scrapped the oven and used an old glass fronted fridge with 4 racks for Mk2.
Mk3 as shown in Keith157's post re CyderPig.
Give me a bell, you can find my number on my FB page or my website, only to glad to help.
Homemade Jerky dehumidifier next.
Cheers
Si