The only time I have seen this done was a dune crawler years and years and years ago. I believe they had driveline issues because they went so far as to drive all four wheels hydraulically. They had to use one big ass swivel point though. Not as big as a bus mind you but pretty big. Good luck to ya in the future.
Here in alaska they build them for moose buggys you can get the springs section out of the rear of a duce in a half army tk try a tk salvge yard for the parts with the pivot piece on it they cut the frame in half cap it and fab the two togather make a couple of stops to keep from going to far and all the ones I see usually have a divorced t-case mounted at that joint also. they run 56 in tires sometimes bigger. at the salvage yard the spring pieces can be found for around $50-$150 /forums/images/graemlins/hack.gif /forums/images/graemlins/grind.gif /forums/images/graemlins/crewcab.gif /forums/images/graemlins/k5.gif