The Uncharted 2 live chat is ongoing with Naughty Dog, and Evan Wells just stated that fans can expect another demo to land soon.
"Yes, we're going to have another multiplayer demo before the game hits shelves. The exact timing isn't finalized yet, but it should be available to an even wider group this time, so if you missed the last one I don't think you'll have any problem getting in this one."
Good news then for the rest of us.
Chat is through here.