I have thought about this. I would want to smoke at a temp around 140*F, not 200.
Here's some of my ideas. I was going to acquire an extra ash can, and cut a hole in it. Attach some sort of duct work to that hole somehow. Use another grill (probably a smokey joe would be perfect) to generate smoke and get the smoke going through the duct, up through the ash can, and out of the top of the kettle. I think I could keep the temps really low by generating the smoke outside of the Performer/OTG. You would need to seal stuff up with foil and maybe use a small fan to force the airflow properly, but that is all stuff I got lying around.... ie no additional expenses. The only thing I'd need to buy is another ash can. I am making an assumption that the 3 air vents at the bottom of the bowl are sufficient to allow enough smoke to enter the grill/chamber. if it's not, then maybe picking up a sacrificial old kettle from Craiglist would be a good idea, then I could just cut a bigger hole at the bottom.
I was thinking that maybe you could generate the heat/smoke in the ash can. I'm not sure how safe that would be.
But heck, Alton Brown has made smoked foods using a flower pot, a gym locker, and a cardboard box as a smoking chamber on Good Eats.
I got the "Charcuterie" book for Christmas, but I havn't spent any time with it. I wouldn't try anything like this until May when the weather warms up around here.