Would love to see a tab somewhere or even a stationary vault (maybe at players starting area) where a player can drop off items. maybe offer a rent fee of a few copper per month and pay more for more spaces. I realize that backpacks and belts are rare items to acquire so to keep these items in demand, make the vault an expense a player has to manage. If the player fails to pay for rental space, all the items are returned (and player may be encumbered and cannot move in game).
I also realize a temporary vault could be the auction house. Players list their stuff for astronomical prices so nobody wants to buy them, but again, the tax to list the items and the amount of time the auction of the item has to be a cost prohibitive method to store items in the auction house.