Don't think about buying one ''chinese new'' (if You like to gamble, go on) - You will have, as others say, old MB with 300+ hours of talk time and who knows how much stand by and using time.
Try UK's eBay, there is good few of N900 there and I saw couple ''brand new, mint condition'' there. The catch is to convice english chicky monkeys to send it overseas, it's realy hard to do. But most of listed there are fairly described, with (well in most cases) Q pics and description (from where the device is, why it's for sale, etc.)
Try to be patient, You never know when another ''minty'' will come out from storage.

Good luck.