Inspired by this here, I had the crazy notion last night of approaching Mr Prowse to film the death scene from Return of the Jedi and have it as an alternative track to Seb Shaw.
Rough Mock-Up Time :
I have nothing against Mr Shaw's performance, he was the best person to play a character called Anakin Skywalker in any medium but like Chewie getting a medal it would be an interesting what if moment made real.
A donation to one of Mr P's many charitable courses would probably satisfy him in terms of payment and keep the project non-profit. He is old enough to play the aged aspect now and could be beyond caring what Mr Walt Lucas has to say on being an unpaid extra on an extra in a non-profit fan-edit.
He might not need the full make up as capturing his facial elements could be enough and I think he could do another voice if asked.
Remember on set he was asked to deliver his lines not act them in another accent.