Would be hard to find a better option then the 9 1/4 you already have in your Dakota. I think I would cut the bed sides for the tire clearance, and mini tub the bed if needed, then run wheels with less backspacing then the OEM Dakota wheels have.

As long as the pinion nut does not come loose, and the wheel bearings don't ruin the axles, the 9 1/4 rears were pretty tough. I believe they are capable of handling a lot more HP then you are looking at, and your truck will be mostly a street truck. Drag racing with big sticky slicks, front tire lifting traction, and more HP then you looking at, might change my mind.