Here are some options for you:
*Launch an Executive Email Carpet Bomb (EECB) to all the executives of B&N. That way, you are bypassing all the Call Center folks and getting to actual corporate employees, who have the power to make real decisions.
*If you get no response from teh EECB: File suit in Small Claims Court. Or even just threaten to file for small claims. When B&N gets the notice that you are going to take them to court, they'll likely settle. It's cheaper for them to pay you $x + a Gift Card than it is to pay their $200/hour lawyer to show up in court. And if they DO say, 'go ahead and take it to court,' it usually only costs a couple bucks to file (depending on your state). Given your level of documentation, you have a pretty good chance to win (IANAL).
*File a complaint with the BBB against B&N. Describe the issue and the outcome you'd like to see. B&N will almost certainly respond.
*Consider returning the Nook and never doing business with B&N again. There will almost certainly be another product in the not-too-distant future that will be better than the Nook, and hopefully they will have better customer service.