for the price I cannot see them being real ! thats the trouble with eBay, also this double your refund business doesn't cut it with most people, as there are sellers on eBay who sell fakes that put this. Also most people buying the fakes dont even know they are buying fakes they think the seller gets them 'cheap' but as you know yourself they are far from it.
http://reviews.ebay.co.uk/A-guide-to...00000002836808 maybe try rewording this, and add it to your listings for people reference, as it then seem you are adviseing the customer on spotting fakes within your own listing, giving them the confidence that you are selling the real deal.
Have you thought about your own website? pull the sales from eBay, and maybe throw something in with the sale! I did one on mine a while back, where are threw in a free t-shirt for a certain amount of spending! work very well
Dave