David,
I put a 64-bit V3 image (image format 68002) here:
https://drive.google.com/file/d/1q-3CtzrRM6ECdeopshZX2OEo1EOpZXiT/view?usp=s...
Images in this format were never really published, although there were a couple of them available on squeakvm.org at one time.
Thanks! This worked perfectly for me. As I expected, the 64 bit VM didn't have any problems. I got 99 million bytecodes per second and 4 million sends per second. It is interesting that this is slightly faster than the numbers got for the StackVM (though I can't be sure there are no differences at all between our boards).
My next option would have been to search for the script that was used once upon a time to convert 32 bit images to 64 bits.
-- Jecel