Sorry guys! Ive been traveling a lot lately and just got to reliable internet. In Colorado now and headed to minneapolis next. Here goes!
Mine was done by American Spring & Axle in Flagstaff. Scott over there is a master, builds jeeps, buggys and trophy trucks. We actually removed the leaf springs, cut the rear spring hangers out, flush with the frame rail, chopped them down, and rewelded them on. It takes a laser alignment rig to get it all set back up perfectly aligned. We then cleaned and reprinted the frame in that spot, reattached the leafs, and used new U-Bolts. I decided to keep spring under, as I typically drive my H3 to the trail, most likely 100 or so miles away on each trip, so I wanted to retain some good on-road characteristics. Cutting the spring hangers down meant that I also lost lift in the process, so in addition to the extended rear shackles(which I remade out of 3/8" hardened steel btw, the 1/4 was actually flexing under load) I also had to re-arc the leaf springs with a steeper curve. Here comes the controversy. Re-arc'ed leaf springs can have a tendency to feel 'harder' on the pavement, and they can droop over-time. The plus side is that if you keep it modest, you won't have to buy a new high-angle driveshaft, and youll mantain no risk for axle wrap. I haven't seen any droop, and don't feel that they came out 'harder', so it's been a win-win for me so far. At the time, I also had new poly bushings pressed into the leafs, and had the leafs rebuilt with new anti-friction slides. All of my squeaks went away, and half of my loose rear end issues went away. I haven't had many Clearance issues really ever with the spring under setup, and my clean-ish Hunner shock skids prove that. Since the shocks are mounted fairly close to the tires, the tires themselves usually lift the shock mounts out of the way by way of simple geometry. It would take a special situation or a pretty gnarly angled rock to cause some issues there, and I just haven't seen any issues yet. My biggest clearance issues were with that front spring hanger of the rear leaf packs.