Well, the cat is out of the bag. I was keeping this work a secret from one of the D8 Night Players, but that player has started down the path toward making a new friend and knows the book exists now.
In this great guide, I've developed a really unique and in depth alternative set of rules for making a little buddy.
I hope you'll check it out and let me know what you think. It is available for free/PWYW on the Dungeon Master's Guild.