Sorry, I haven't seen them before, but they're gorgeous! Did you try calling the Chanel 800 number?
http://cgi.ebay.com/BRAND-NEW-AUTHENTIC-CHANEL-SUNGLASSES-4136-127-87-BLACK_W0QQitemZ140205077075QQihZ004QQcategoryZ45249QQssPageNameZW
DVWQQrdZ1QQcmdZViewItem
Found them on ebay, looks like a good price...