I saw dozens of add-on type mini-displays at CES this year. They are already fairly cheap (many were priced around $129) and most are USB powered. Looks like a pretty convenient way to leave a certain Web site (weather?) open all the time.
It’ll be interesting to see how they get used. Logitech was showing a gamer keyboard with a little 2-inch by 3-inch display -- the color GamePanel LCD shows game stats, system information, communication data, video playback, image slideshows, or other information, without leaving the game. It seemed to be a solution in search of a problem to me, but it sure did draw a crowd. Go here to watch the video.