Could be.... hmmm. Wasn't the ILM X-1 miniature made from a standard TIE fighter? You could probably do just that, replicating the model shop's process.
What makes the X-1 kit's 'ball' awful, Jimmy B?
Cheers and Regards, Robert
There are no panel lines, and it's a smoothly blended conical shape at the rear instead of a standard TIE conical ring.
You can see photos of it here. The cockpit hatch is also pretty terrible. There'd be a lot of other detailing work to do, but they're what scream out at me, anyway. Clearly, the Bandai would be much better (except for the out of scale panel lines), but where's the fun in just glueing a kit together?
With the Revell kit, I don't stress too much about inaccuracies in the greeble parts because my philosophy is if ILM had had to build a 1/72-ish scale TIE for a shoot in the 70s and 80s, they would have only used similar looking smaller scale parts from their boxes of kits anyway which we see in actual versions of miniatures: a kind of "what if" studio scale miniature is good enough for my shelf as long as it looks the same when I squint my eyes lol.
As an aside, Super Hobby, which I linked to above, is very useful for when you want to see what's inside a box. They have sprue scans with a ruler for every kit they ever stocked, so you can get a good idea of what kits to consider if you're kitbashing or scratchbuilding a project.
EDIT: I just did a quick measurement on my monitor screen of both the TIE fighter and Vader ball diameters using the Super Hobby photos, and the Vader TIE seems to be quite a bit smaller, so the idea of swapping balls is busted anyway