Fire up your smoker for 225 F. Use any wood you like, these turn out great whether they are smoked over fruit wood or a stronger wood such as mesquite.
Squeeze the mustard over the dogs then brush around all sides. (I found it easier to just spread the mustard with my hands).
Sprinkle the rub over all sides of the dogs. Transfer to your smoker and smoke for 1 hour.
Meanwhile, fire up your grill for medium heat cooking (or pre-heat your oven to 375 F).
Remove dogs and cut into thirds (about 1 1/2" pieces). Transfer to a disposable pan.
Combine the butter, brown sugar and BBQ sauce and pour over the hot dogs. Stir and place on your grill (or in the oven).
Cook dogs an addition 30-45 minutes, stirring every 10 minutes, until the hot dogs have begun to caramelize.
Remove and let cool slightly before serving.