Have you ever thought to freeze avocados? One person did and it worked very well:
Worth a try, I think,
I have. As either a pre mashed packet in ziplock bags or whole frozen. When you defrost, the cold water trick is not entirely necessary to retain the color as much as it thaws the mash quickly. But freezing does change the avocado. So once defrosted, whether mashed or whole, is best for guacamole, spread on a sandwich or in a dip.