Any reason why though? I mean I kinda get it,.. But really, is it necessary? I too ran into an issue where I needed to go back and add something and couldn't..
I go on other sites with similar marketplace forums, and it's nice for instance if you got a whole list of stuff for sale, you can update whats been sold and whats still for sale. Or you can announce that whatever you were selling has been sold.. I've seen on more than one occasion where someone will inquire about a listing thats a bit old, and have to go through the trouble of finding out that it's long gone the hard way..
Just trying to give some constructive input..