Why do people want the Diesel so much?
You're surely going to pay a premium for the engine itself, perhaps as much as $2500 Plus for that option alone. That, as well as, being only available in the top of the line model of the Wrangler series, adding even more to the price, and then guessing, in the Unlimited model only.
Then there's the cost of the fuel, not only is it more expensive than gasoline, and limited when it comes to it's availability at gas stations, but w/all things considered above as well, you won't gain much, if anything, other than of course, having the engine.
Then there's the potential cost of repairs, the general maintentance, then there's the problems of the tranmissions, w/automatics being the only ones most likely available, even holding up to the torque of the diesel engine, as well. I'd definitely buy an extended warranty for sure, so there's that cost as well to add to a diesel package here.
Then it will most likely have to have a Turbo, if you want any decent performance from the engine. When Turbo's fail, and they do, they can cost a lot, as much as $2000 alone for an OEM. Again, you'd want that extended warranty.