1) Take the rear end out of a 2003 (I think!) Dakota of the same wheeledness (2WD/4WD), and have the proper shock mounts welded on, then use it with a new drive shaft due to the different yoke on the pinion.
2) Take the rear discs off a 1996 or so Grand Cherokee, and have the rotors redrilled for your 6 lug pattern. Take it backing plate and everything out.
On either, I'd put new axle bearings and seals in while doing.
A third method would be to convert to 5 lug patterns (1987-1990 Dakota front rotors, which come with the hubs, for 2WD; I THINK that for 4WD you can do a hub and a rotor and be good, but am not sure, in the front - for the rear, proper sized rear drums from a 87-90 Dakota and new axles) and then you don't even have to drill the rotors from the Grand Cherokee.
That's what I've found so far. Since mine is a 1988, I'm opting for the Grand Cherokee method later (I have other work that's more pressing to me.)