The only thing that needs to be addressed is leaving feedback for the buyer. For example, lets say bottiger bought a bud from me from my trade thread. He can leave me feedback for that trade. But as the seller, i have no way of leaving feedback for that trade.
I think the best solution is that if you are the seller, you should be able to link your rep to your trade thread as long as the person has posted in that thread.
so lets go back to my example. bottiger posted in my thread "i will buy it add me". i add him. I can now leave feedback for bottiger, by clicking on my thread.
I don't know if this can be implemented or not, but i think thats the best solution if we want to keep this setup.
Which by the way, i do like.