I've built a PID controller unit for anything, It's a box with a temperature probe on a wire and an outlet. I can plug up to 1500W into it for an electric smoker, dehydrator, sous-vide, bathtub pig, or smoker.
If you do some research you can find the right type of PID controller that will switch up to about 3A of AC or DC or one that turns on a DC output without the need to a SSR. This would be ideal for a smoker where all you need to do is turn on a small fan. I've seen some that need powered by mains on AC, and some that run on DC so pick your controller carefully.