I would recommend a Montero in either the Gen 2.5 with a winter package or the Gen 3 with the 6G75 engine ('03-'06). They are reliable, overbuilt trucks that have some real advantages over the competition, IMO.
The 2.5 is (subjectively) a great looking truck with a solid rear axle that was available with a factory air locker ('98-'99 winter package). The transfer case is manually selected and has a true 2WD setting as well as full-time 4WD. Locking hubs are an easy upgrade and low t-case and diff gears are available as well as aftermarket air lockers. The Montero also has a rear mounted spare, real third row and a gigantic sunroof. This would be my pick (I owned two) for a more offroad oriented overland rig.
The Gen III is the pick when a more road-oriented rig is required. It's no slouch off-road (has a record holding number of wins in the Dakar Rally) despite being IFS/IRS and has an incredible traction control system. It's a monocoque body design which is stronger than a unibody (and, since you're looking at XJs...). The last year for these was '06 in the States so they don't have as big a following as some of the other platforms, but there's a wealth of information worldwide under the "Pajero" search term.
The biggest drawback I can think of is that the service intervals are very short for things like timing belts and water pumps and, unlike other makes, they don't have much of a safety margin built in. IIRC, the timing belt interval is only 60,000 miles. When I did the TB job, I reused a factory tensioner that tested out ok per the manual and it ended up fragging the engine (interference type). Access to the components is also a bear. The entire intake manifold as well as the upper and lower plenums have to be removed just to access the spark plugs. They also have a very slim aftermarket in North America, but that seems to be picking up as more people are building them.
The biggest mechanical issues seem to be oil leaks (cam seals front and rear, valve seals) and crank bolts that walk-out on their own (fixed with updated OEM bolt and washer).
My current rig is an LX470 which suits my family better for a variety of reasons, but I often miss some of the features of my Monteros.