Sorry to be so, um, realistic, but you're looking for a needle in a haystack. I would consider buying new. I don't know that I've ever seen an electric Chevy SMB top on anything but maybe a new, full build.
Westy tops are simple to raise and install but getting really hard to find.
Ford won't fit without extensive mods and electric ones are really rare.
Do you like to do fiberglass work? Metal fab?
I don't at all blame you for posting up a want ad but just trying to keep it real, this is not going to be easy to find. If you want this to come to fruition in the next few years I'd just buy new, and I'm not sure who does new tops on Chevys nowadays.
Welcome to the forum, and good luck!