I took your advice and called Nikon. They advised that if it is US Nikon product and purchased it new from Ebay, my Ebay purchase printout would serve as my proof of purchase and the warranty would be valid. Just to be sure I called and spoke to a different associate and this was confirm. Also, they told me that service would be provided on a US nikon even if there was no warranty.
Don't gloss over these parts. If the seller is not an authorized Nikon reseller, you are almost certainly NOT getting a US Nikon product. Therefore you will have NO warranty and NO service from Nikon USA - ever. The seller may provide a warranty of some sort - that's what B&H does when you buy an import from them - but it's worth checking very carefully on this.
Note also that Nikon presumes you are guilty until proven innocent. You must prove that the product is a Nikon USA import, and often that YOU purchased it, to get service or warranty. Often the former is easy since many current products include US in the serial number, but sometimes it is NOT so easy, especially if you give Nikon some reason (rightly or wrongly) to believe that something is a grey market import.
_____ Brian... a bicoastal Nikonian and Team Member
My gallery is online. Comments and critique welcomed any time!