If the highest possible roofline is your ultimate goal, the XJ is a very poor choice for a starting point.
My SuperDuty is about as tall as an H2, I parked next to one a couple weeks ago. Right now I'm parked in the driveway next to my girlfriend's stock Cherokee, and her roofline is maybe 2-3 inches above the Ford's bedrails. I think my back window is in the neighborhood of 25" top to bottom. So you'd need something like 22 inches of lift (susp & tires) to meet your goal. Figuring 28" tires stock, that'd be about 14" of suspension and 44" meats. That's an awful lot of work and money just to match the profile of my F250 or your friend's H2.
The Cherokee is a very capable little rig, partially because it's so compact. It's just not going to be huge and hulking.
The better way to show up the H2 owner would be to simply invite him on your next trail ride...
Robert