My 08 came with a lifetime power train warranty, as well as the normal 36/36 bumper to bumper.
I just check www.ChryslerWarrantys.com
and they are asking a little under $2100 for the max plus coverage with $100 deductable lifetime.
What that coverage still does not cover is ware items, and items damages due to use/misuse, and normal servicing.
It's an insurance policy, and just like any other insurance company they are in business to make a profit. They've run the number, and know as an average they are going to make money on the deal. If your hard on your Jeep or you expect to keep it 10 plus years, then it would be a good deal for you.
Some of the parts not covered by the lifetime power train coverage can get rather expensive, but I'm sure within a few years aftermarket company will have them available