Commanche Dana44s might work as is. Those have spring pads underneath and no shock mounts just like the Concord has, and the spring pad width is the correct width.
I disagree about 2WD rims not working on an Eagle. If you measure the outside of the fender flare to the tire on a stock Eagle arrangement is comes out to about 2-1/2 inches. That is hideous. I add a 2" spacer to make up for that or I use a rim that offsets the tire about 2" further out, like the factory Spirit AMX rims. Visually the tire should be about 1/2" in from the fender flare.
The WMS of the Eagle, MJ, XJ, and TJ axles are all about 61". CJ axles are about 54" and Scout axles 58". The ideal WMS would be about 65". For about $1200 on ebay you can have a Dana 60 shortened to that amount and even given 5x4.5 bolt pattern with disk brakes. Look at posts intended for TJ or YJ post and there are currently several people offering them.