The IH Scout II's Dana 44 is about an 1" narrower on each side. It runs 5x5.5" bolt pattern (same as a CJ). Due to the hub center's size, it can't be drilled to the MJ's 5x4.5" pattern, but you can get adapters to change it and with them, you'd be about the same as stock. The Scout's rear axle doesn't come with disc brakes, but they are bigger than the Jeeps - and if you get a '75 or newer, they are bigger than the pre'75 models.
I used one from a '73 Scout II in my XJ (partly because it was scavenged from a rusty parts rig for free), but I didn't use adapters because I wanted to keep the 5x5.5" pattern and with the different offset typically used with 5x5.5" Jeep & Scout & Bronco, my track width actually increased with the narrower axle. I did have to address the front though, otherwise I'd have to carry two spares. I chose to build a hybrid full-floating high pinion D30 out of my OE axle. http://www.4x4wire.com/jeep/tech/axle/xjupgrades/
Why not just run an Exploder 8.8 with discs?