Though it's a bit blasphemous, the 4.0L is a good engine. I think you would have to use the tranny/x-fer from the Jeep as well, as I doubt any adapters are available. Someone on here swapped a Jag V-12 into a 40, so anything is possible.
I wouldn't buy that sight unseen. That looks to be some substantial rust for something billed as clean, and who knows what's been covered with filler. My dad always warned me about white "restored" cars, i.e., "bring a magnet."