Pardon my off the cuff suggestion here...it is somewhat of a whimsical idea, but:

What if there were a feature, that allowed you to place your goods for sale, with a single consignment merchant in each major city...

A completely separate facility from the market wards and retainers.

And this consignment merchant had reps out in the field as well as in the city. You're taxed and a small fee goes to the merchant, then upon sales your returns are sent to you...(I hate to say it, but, a la FFXI)...

Perhaps, a simplification could even be that the NPC sets the sale price. Maybe it's even smart enough to look at the avg or the current high price of the same item in the Markets.

As the game matures and supplies become a more important part of the game, I could see this as a useful facility for selling goods such as ammo, arrows, potions, and other consumable supplies.