Well, although you seem to have made a decision, I'll throw in my opinion anyway
The short answer is there is no one piece solution that exactly duplicates the ROTJ pommel.
What I've done is taken the main tube, slipped a short section of thin walled PVC or plastic pipe around that, and then mounted the "cubes" (fashioned out a larger section of PVC pipe) around that. Then, depending on the desired finish, I either painted it or covered it in silver HVAC tape.
Some time ago someone fabricated and all metal ROTJ v2, using various diameters of aluminum pipe to achieve a similar result, building up the "cubes" layer by layer.
A simple answer might be to download a file from Thingiverse or the like, and have it printed up locally (libraries in my area are starting to offer that service relatively cheaply).