Had this idea way back when we were still guessing about what the year of the beefalo would introduce. A Saddle bag "belt" for beefalos that can only carry beefalo accessories.
Beefalos are great with a piggyback because they negate the speed penalty, right? But then we have to dedicate a few slots to the beef, whether its a brush, a bell, a war saddle or glossamer saddle, and a saddle horn. Obviously you can just not carry all of that but encouraging saddle swapping on the fly would be pretty cool. I also suggest requiring a bearger pelt to gate it behind a minimum of 1 year of progress so 3 slots don't sound as absurd.
Bonus if it can carry grass/twigs and manure.