To Strelets - Separate, attachable packs with Generic animals ...
Carlos and Uwe make exellent points above.
Personally, along their suggested lines, hopefully you could consider a Strelets-Mini set of 4 identical sprews, which each sprew has one each of the horse, mule, camel, etc, and separate attachable packs including maybe boxes and bags bundled, a maxim machine gun on back-rack, a small mountain cannon on back-rack, a double stretcher set for wounded soldiers etc.
It would be so easy to sculpt the animals in walking/standing poses with a single peg on top about 5mm tall in the center of their backs, and make single sculpts of the packs with a hole all the way thru them (just like Roman shields).
The packs could just be pressed on the animal with no glue, and in the Mini format, 4 identical sprews would give the customer at least that many options, or buy multiple sets (like me) and make a huge, long pack train ... just waiting to be attacked by enemies of ancients, all the way up thru Colonials and WWI (even WWII).
Even if not separate Mini sets, then it could be a great accessory set to be included in a Big Box format with other command sets. We wouldn't need to buy so many Big Boxes to have a lot of pack-train options, and packs could be swopped as many times as the customer wants for different themes.