Why no water in the pan? My understanding is that it the water gives the fat dripping off a place to go that will not flare or interfere with the smoking process. Also, cold smoking meat, which has been mentioned is bad for safety reasons. Cooked, smoked, or cured meats are a different story.
The collagen in the meat doesn't break down until somewhere around 180 degrees F, or so. If you want tender meat you will need to cook enough to break down the collagen, which also makes the meat really juicy. I smoke pork butts at 225 F until internal temp reaches 165 F then wrap in foil and continue to cook (without smoke--it wouldn't get through the foil anyway) until internal temp is 200 F. Onto the grill sans foil finishes the bark to a crispy goodness. Can't imagine how sous vide could help after smoking, but cooking first, then finishing in the smoker might be ok.
I'll be interested to hear the results.