The exact same thing happened to me recently. I received an e-mail at my registered eBay e-mail address, which isn't known to anyone in the eBay community until I buy or sell something.
I knew the e-mail had to be fake right away, because I was not even the under-bidder, I was like 9th or 10th down the list! What sealed it is the message wasn't in My Messages on eBay when I logged in.
I reported my incident to eBay as spoof e-mail and asked how this con artist could have matched up my eBay user ID with my eBay e-mail address, but I never got a reply. I was left to draw my own conclusion, which was either it was someone I had bought from or sold to in the past who was monitoring my buying activity, or someone hacked into eBay's server or another eBay member's computer and got info about their customers.
twoinvallarta, were you the runner-up for this item, or further down the list? Either way I'll bet that some other losing bidders on this item got spoof e-mails too...