If you don't want to build your own, the green egg is a really solid ceramic smoker/oven. expensive but the results are consistently good.
Mine is almost exactly like this one, except that I replaced the top pot with a ceramic lid. https://www.youtube.com/watch?v=ZAydLWYGoJA
I've been thinking about building a PID controller for it (I already have the equipment from a project I did for an embedded systems lab in college), but I'm worried I'll end up eating way too much barbecue.