There are a variety of Rockwell Axle Jeeps out there in the world. The advantages to Jeeps and other short wheel based rigs using Rockwell 2.5 ton differentials is the short wheel base and the restricted turning radius of the large military rig axles. Effectively overcome in larger sized rigs with four wheel steering, smaller rides can use one steering axle. When equipping your rig, this makes things much more reasonable.
The biggest obstacle with toploader military axles and short wheel bases is similar to the issues in other trucks. You do need an additional 7 inches of clearance over conventional front loading axles. Of course the best answer to this is to relocate the front axle forward and the rear axle backwards which is easily performed with the body lines of most Jeeps.
My next Jeep Rockwell build would be a YJ based rig. I would use YJ Springs up front, with a doubled up long spring (from the rear pack) and I would build a custom front end stinger that incorporated pushing the front axle forward 6-8 inches, enabling the motor to sit behind the axle top end. I would run XJ springs in the rear, to push the axle backwards with additional axle wrap control, or 4-link the rear end, pending finances. I would run 39-42 inch Iroks with Hummer double beadlocks recentered for the rockwells.
Additional additions I would think about to keep costs low would certainly be to take advantage of the toughness of these axles. I would weld the spiders (for budget) and then run a split manual brake system using pinion brakes, with a twin sticked transfer case to independently brake the front or rear axles for front or rear digs. To run 39 inch rockwells and tires I would shave the bottom end and add a custom skid pan available from a number of vendors, or custom made from our own.
I have come across many jeep based rides with Rockwells and for good reasons. They frequent the Top Truck Challenge, and other situations where money is taken into account and you can live with a few extra hundred pounds. This is usually OK in most wheeling genre’s except for specialized areas of rock crawling or desert racing.
Overall, military axles are a great setup to base custom wheeling rigs around, especially short wheelbase rigs. Given some of the challenges that are associated with the top-loader style, you will need to go with some custom suspension which would require some fabrication beyond a off the shelf lift kit.