[3wbdriver]

I may be talking out the wrong side of my mouth (actual experience being zero), but it seems to me if you go with a shorter sidewall, you will be INCREASING the harsh ride characteristic.
I am a roundy-round dirt track racer by hobby, and we all still run 15" wheels on our stock cars. I believe the main reason for this is because it allows the side wall to flex, allowing the tread to maintain it's contact patch with the racing surface longer.
Road/Sports car racers are running 17-20" rims because they want minimum flex, allowing them to tune their suspensions without giving up too much spring rate to the tire. They actually want the harsh ride, to maintain maximum adhesion on a smooth surface.
Pro Offroad racers do run 17-18" wheels, but they are doing it with 36-38" tires, and I think they are just trying to keep the amount of side wall to a reasonable level. And they run soft spring/shock setups, with lotsa travel.
Short of custom tuning your spring/shock package, I don't believe you're going to get that wonderful - I actually love the feedback - bounce out of the ride. Especially with a SWB, live axle/leaf spring setup. That's the main thing that began the death of the CJ-5 in the 70's-80's. It just wasn't "comfy" on the road to the current generation of drivers.
But, like I said earlier, I may just be blowing smoke. I am just an old fart, who's nostalgic for the older, simpler rides of the pre-gas crunch era. Hope this helps.