My gut tells me this is authentic. But I cannot see the sellers other auctions because they are all private. S/He seems to have sold hermes in the past, but it is hard to say. Feedback looks good....hmmmmm.
I honestly have not seen this faked, and you are right they are hard to find...I wish I could be 100% certain, but all I can say is that if it were my grail, I would probably pull the trigger.
Remember, you only got a babbling opinion there, not a professional authentication.
Proceed with caution. (<<--paypal/Amex)