I don't literally want to do a straight trade for a 5850 for one of my 5870s, but if I were to sell on eBay the fees after PayPal rip me up. Half my use of bitcoin is to get around this whole world.
Although eBay+PP charge about 12% in fees, because of the number of people bidding in that environment, you get much higher return in the final price. Check for "completed listings" on eBay to see the prices you would get. I tried listing a brand new Sapphire Xtreme 5850 here, but all I got was a low-ball offer.
I do have a used Sapphire Xtreme 5850 that I want to sell, but not trade
I have enough cards I want to get rid of. Actually I can sell 3x 5850s to you if we can work out a cash/btc deal. PM me if interested.
Further I want to make a second machine for my girlfriend to run at her place and use when she needs it for school. 5850s are a little cheaper and run lower on power, so ideally I'd like to own four of them (I have one currently). I'd, for example, love to trade the two 5870s for three 5850s. I think that's close to market accuracy, no?