I love the sous vide method of cooking; my favorite is tri-tip cooked for 2 hours at 135 degrees and then reverse seared over a rockin hot grill of pecan wood. I do chicken the same way and it always comes out awesome. As far as using it in a competition if you could maintain the water temperature using wood based fuel there should not be a problem since you are not parboiling (i.e. water never touches the meat and the h2O is not at 212 anyway). The biggest hurdle is the smoke flavor and the bite though of the skin which really should not be too hard to overcome.
Qholics BBQ Team
New Braunfels Longhorn Deluxe smokers (2)
Weber Gold Kettle 22 1/2"
Inexpensive vertical gasser
Maverick ET-732 (2)