My friend had a cool idea.
What if Leatherworkers could make a "Saddle" that could only be used on beasts.
So you would take the "Saddle" out to say, Borean, and use it on a Whooly Rhino. Then that would be your mount.
You could only have the Saddle attached to one beast at a time however so you couldnt have unlimited pets.
IDK... kind of a neat idea. Thought I'd post it.