I like the idea of the auction house or trading source, It allows players to make money from sources other then selling to stores, and for adventures this would be awesome, I tend to get stuck with alot of products I have no need for.
My other idea and opinion for the auction is it should only allow you to sell products only. This will allow people whom are having issues with certain quests I.E. union flag quest to pony up insane amounts of money to just move on a bit if they have the cash.
I do feel that selling town buyable items, though should not be allowed, as people who have good items in here town like Clints Poncho or a gold cross, could sell them at auction and just start making insane amounts of money from people who could still get them at a discount but not want to travel to get the item. This is why I feel it should only allow products to be sold.
I hope this comes to a reality.