I'd love to build something like that someday but I would not know where to start. There is a guy on NAXJA that was building a 4 door truck from an xj front and mj back. It's for sale last I saw.
I saw a real one in Emerald Isle. in October. It was stock wheelbase and had 4 doors and a small bed on the back and was fabbed very nicely, it looked factory.