A buy and sell forum has been on our minds for a while. People seem to want it, however there are two big forums that already do it, and I think one of them does it very well, that being fredmiranda.com
I imagine Fred spent a considerable amount of resources to develop the rating and feedback system, I would have to find a developer that could implement similar features. I would also have to find an angle that would make the buy and sell here unique to the other sites. More of the same rarely works out.
The other issue is policing it, and watching for scams. Even though it's not the web sites fault, when someone does get scammed, we're going to have to deal with the fallout. I'm not sure I really have the stomach for that.
I'll think a little harder about it, a few other things are being implemented in the next 30 days at CR, so I'd like to get all that done before we take on another project.
Thanks for the great feedback as usual folks!