many people do this--"the Alton Brown smoker," and it works very well. I used one for about 4 years and it was great. They don't control temperature as well, however, and even with a PID, the do-it-yourself version with a hot plate and small woodchunks is going to require more hands-on-attention than a large kamado with a serious convection design and a fire ring in the bottom. Granted, I went with whatever cheap and large cermaic pots I could find, and they didn't fit each other perfectly, but it worked.
PIDs with blowers that control the flame are pretty common these days
https://www.bbqguru.com/StoreNav?CategoryId=1&ProductId=34&keyword=&gclid=CLnzodjsqNACFZBLDQodh88DSw
and apparently work very well. I've considered getting one myself, but I'm a fidgety person and would rather miss the constant OCD treks out to the backyard to check the temp and fiddle with the air vents for no reason. But--these are great for overnight when you just want to get it going and sleep peacefully knowing it will work out in the morning.
Many people just tack that on to the bottom of vent of their egg of similar kamado, set the temp, and walk away.