past ebay auctions are usually a good indication of market values - although in the end it really boils down to what you are willing to pay and the seller is willing to let it go for. this one in Germany right now is the best analogue i think and around 1000Euro would have been my guess as well (and i am a Merlin addict and closely watch the "market")
here's another one and the higher price reflects the blingbling new XTR parts i guess
prices in the US usually are between $750 and 1000.
Does the one you are looking at have the 1 1/8 or the 1" head tube? For some the old 1" adds value for others not.