They're also selling a PSR3000 for the same starting price and someone has bid on it already. Very strange to see that they have 3 of each unit for sale. Even the PSR3000 picture is taken from YamahaPKOwner.com. Surely if these were legit the seller would put his own picture of them on for sale.
There's far too many suspect dealers on ebay when it comes to musical instruments and to be honest Ebay seem to be doing very little about it.
http://cgi.ebay.com/NEW-Yamaha-PSR3000-W...1QQcmdZViewItem