CJ D44 is too narrow.  Even if you use a widetrack it will be too narrow.  Not to mention the bolt pattern will be different.  Although I guess you could use wheel spacers to make them wider while also changing the pattern.
There are a lot of other choices;  XJ/MJ D44, Scout II D44, SJ D44, Isuzu D44, J-Truck D44, etc... Or go bigger with a IH Travel all D60, J-Truck D60, Ford 9" (LTD/Grand Marquis/Lincoln Town Car, 4.5" bolt pattern + Disc brakes) Early Bronco 9", Corporate 14 Bolt...  For a TJ, the easiest bolt-in is a TJ D44.  You could also go with a custom axle.  Even with a salvage axle, once you get done with replacing gears, shims bearings, seals, brakes, add lockers, etc, you'll probably have around $1000-1200 invested in the axle.  You might also look on other forums for people selling off their old axles.  There are pretty good deals out there for people upgrading.