Swapping axles and stretching the wheelbase isn't all that hard.
Especially YJ's are easy to do. Outboard the spring hangers upfront,move the shackes in front of the frame for a nice stretch use XJ springs roll a HP Dana 44 or HP Dana 60 under there and button er up. Move the steering box forward some use an Astro pitman arm and things start looking pretty.
In the rear just move the shackle behind the frame roll a Dana 60 or a 14 bolt under there with the same xj springs and you get about a 109" wheelbase.
Ford shock towers all around for some 14" travel shocks and you are starting to get there. Pretty simple eh. I helped a friend do this took me about 4 hours to get everthing cut out of the way, tacked front and rear bumpers tacked all the hangers, mounted the axles and had it sitting on it's on weight. Couple of weekends later welded everything up, flexed it and then welded all four Ford shock towers and shock tabs on the axles.
Since then my bud pretty much figured his steering out and it looks pretty good to me.
My Tinkering and wheeling thread http://tinyurl.com/pbwdm5u