true, i was ready to get rid of the TTB shit under my bronco as well. they work well in a factory suspension, but when you start lifting the TTB, they want to cooperate less and less.
i dont think you're gonna find a direct bolt in. but there are several choices of axles to choose from.
if you found a FW 44 from an earlier fullsize bronco or ford truck, you'd have to swap out the axle, the radius arms and the raidus arm frame mounts (which may or may not interfer with your trans cross member).
a leaf sprung solid axle would require you to modify the axle to accept coils, (lots of companies make brackets for that though). or modiflying the frame for leaves.
if it were me, i'd find something already set up for coils and modify whatever i needed to swap it in.