OK well here's my contribution for the day:
This is the IFS version of the Ford 8.8" axle. The biggest problem that I can see with this one is the fact that the mounts are fore and aft as you can see (and it's just a bad angle... the rear mount isn't actually lower than the diff). The offset is pretty close to that of a CRD with 3.5" coming out of the driver's side of the diff. The other side is about 13". The hub-to-hub difference on this assembly is about 10" wider than ours. I haven't torn into the front of the KJ just yet but I doubt if there is room to build mounts on the front and rear for this. If someone else knows better then let me know....
The rear end is another story though....
I had no idea how similar our rear setup is to the Expedition. This huge rear has coils and trailing arms just like ours but they use a cool looking I-Beam panhard bar instead of our wishbone. You would lose 1" of clearance at the pumpkin with this axle. The only modifications needed (aside from driveshaft would be to move the shock mounts, perches, and control arm mounts. I also like the idea of that panhard bar (assuming you could find a place to weld the mount) a lot more than our wishbone thing. The control arms on the expeditions look like they would bolt right onto the KJ but are 2.5" longer.... hmmmm
The rear coils are a good size too... they may just work for a lift on ours if the spring rate isn't outrageous....
Well that's it... I'll find another vehicle to poke around underneath tommorrow hopefully.