I recently got a pair of excellent condition TH-600 from here and have been impressed by them, therefore I'm curious to see if / where the TH-900 improves on it. Of course I would be adding cash if anyone would be willing to trade their TH-900. The original box and receipt are here (November). I don't think these would be for sale, I would probably just keep them if nobody wants to trade.
(located in the Netherlands / Europe by the way)