I added a mod. to my DHs grill, but a cheaper option that I've seen(online) is a two barrels, one for smoking, one for heating up your chips, connected by a tube. Source of heat is a hot plate with a pie pan filled with wet chips, to keep your cheese cooler, it helps to put a wet cloth over the cheese or a bowl of water at the bottom of the smoking barrel. Alton brown also had an episode on how to make your own liquid smoke. Not to hard to make, but time consuming.