http://www.amazon.com/Shimano-Ultegr.../dp/B001GSMI7S ?? You'd want to verify the model number and year before ordering of course. Your LBS can get it for you, might be a couple of bucks more, but it would be worth it to be sure (and to give the business to your LBS).
I didn't even know it was called a nameplate until I did my own faceplant. I left the bashed-in nameplates (along with the blood on my helmet strap ) as a kind of badge of honor ...