Making trade on plot/lair consigners more intresting?

Hi i want to suggest an additional Quest/Trade system which could be completely player based and would work additional to the existing trade system.

My thought was to implement a trade at the consigner a player has on its plot/lair and would work like a quest.
A player greets the consigner and the consigner offers them trade quest the plot owner has set up. it could be like:

Bring me (Number and Item Name or Price) and i will trade you (Number and Item Name or Price) for it.

The numbers can be defined by player and may should be limited to not to have over bulk one could hold.
The items wanted to be traded may can be implemented with an option in the existing trade window to set up a trade quest (maybe a checkbox in the trade window or something to enable it to set up the trade as a quest)
the player/plot would need to put in price and items for both items given and items taken to define what the trade quest will be.

The items given would be stored by the consigner and if the quest would be done gives it to the one who does the trade quest or if the plot owner takes it back will get the items back he would have offered. about coin the consigner may takes a charge for each quest set up or a percentage of traded coins.

Number of trades that can be offered may based on the tier of consigner store.

May let me know what you think about this suggestion or if you have questions about it.

Interesting way to allow player designed quests and to get items needed.