your ganna have to measure afew and modify the frame and XJ frame if needed.
Any 1/2ton chevy frame with leafs front and rear I think would be easy enough for you to work with. With the 1/2 ton Chevy frame it will flex so you will need to Isolate the frame from the body with flexable body mounts like a factory chevy cab would mount.
1/2 chevy all the way.
Only question I see is if you shoudl attempt to keep the cherokee Drivetrain or replace it with the chevy stuff on the frame you will buy?
Is the cherokee stuff in good shape? If so It mgiht be worth putting more money into it getting a SYE for the t-case and making new drive shafts. The Np231 I wouldent trust on 44s.
Ideally if you could find a 350 or 454 powered 1/2ton with a Th350 or Th400 auto with the NP203 behind it, you could use that whole setup for now get the project rolling.. I think $500-1000 you should be able to find a ugly ass but stout drivetrain.
and later you could add a chevy Np205 doubler behind the 203. Swap to propane or fuel injection, get beadlocks, upgrade your used tires to new 44in Boggers..Swap Xj boddies if yours gets trashed.
I think this 1/2 frame Idea will work out great for you. not

style but what ever.