Nissan has confirmed to me that the Duke promotion is extended through at least DEC.
That said, how much discount are people seeing now with the 2018s right around the corner. As was pointed out above, if Joe Schmo off the street can get $8k off and the Duke thing only gets you $10k and the dealers are standing firm that they won't discount on top of that, not much of a deal. If, however, you can get the $10k + some extra dealer discount, then we might have a game afoot!
2012 Cayenne Red SL
ODO: 46 upon pickup; ~23k in AUG 2014; 39k in NOV 2015