Nobody mentioned Parnelli jones dirt grips. My buddy ran a set of 38x15.50x16s they were radials not way loud on the road did very well off road. I cant tell you how long they last as he sold the truck. I cant be sure on the actual size but they was BIG I know some 37' radials look like they are really 35's, I can say the PJ dirt grips looked to be close to a real 38.
Not the tire I would recomend for a mostly off road rig with some pavment but you did say DD so thats the best I have seen.