Beyond the End

I have started mercenaries and traveling merchants. They would be visiting your home.
Well, there is no troubles with mercenaries, but traveling merchants has one potential problem - goods container.

Realistic game mechanics, damn it, don't allow to keep goods somewhere in outer space, whiteout dirty hacks (something like your faction hoard, but we have to do this. But I'll fix it dding special hoard chests).
It isn't real problem with static merchants, heave armored chest in the corner and no problems, but traveling one? They must curry goods with them. Link goods container to backpacks, pfff. nonsense, they can't hold big objects. Add super backpacks for merchants? Nope, it is dirty hack and also, they would be hunted down by player for this bags.
Maybe special porters? Or animals?
Ha! I got it!
Traveling merchants would be accompanied by walking chests, maybe from Sapient pearwood. =)
If killed they would leave chest with goods, also, as creature they would be following merchant and fiercely protecting him! And, this idea fits game mechanics very well!