This past November I bought 1998 XJ from the 2nd owner (owned it for last 17 years) with 113k miles, bone stock and rust free. Even then I spent a pretty penny (and many man hours) on maintenance, fixing oil leaks and cleaning up the interior (saggy headliner, dead bulbs, etc.). That doesn't include all the extra money I spent on a lift, tires, steering, bumpers and fender flares.
It would have been much more cost effective to buy something already lifted and with tires. I know you're looking for bone stock but you may have better luck find something that's very clean with work already done to it and can very likely save yourself time and money doing so. I would absolutely go this route if I were to buy another XJ.