What products, deals or other incentives are available exclusively to those paying with Bitcoin?
The only payment method for Bundles through Nestor Games is in bitcoins.
Items in BitPremier's showroom are available only when paying with bitcoins.  Since some of these items are not otherwise available this might indicate Bitcoin exclusivity.   
Author James Altucher made Bitcoin as the only payment method for his new e-book (for a limited period of time)