Swapped to Muscle - 75 Duster Daily build
You could do the Jeep Liberty rear brake swap.
Would take some time to source the parts at the yard (been seeing them at Pull and Save), and you would have to get the brackets machined.
Not a fan of solid rear disks, but I used Grand Cherokee brakes on my Duster and that is what they use. I expect for a normal run around car, they are more than enough.
At the same time, I don't think you would see a marked difference doing from drums to disks in the rear. Tim Werner (Red Brick) ran rear drums on his car for a couple of years and it wasn't until he was hitting 150 on the straights that he swapped (at least that is what I remember).