Samsung has just announced the SyncMaster 2263DX a 22-inch LCD monitor that features an additional 7-inch monitor
connected to the display. The 7-incher’ is a USB display, and is designed to meet the needs of people who want an additional display without the costs or deskspace of a full sized additional monitor.
Personally, they are moving in the right direction, but a screen that small should be positioned above, not to the side. That way I can add 2 more SyncMaster 2263DX’s on both sides! You see where I’m going here?
Edit: It looks like Samsung was not cutting corners with this monitor, the arm that extends the secondary display can be repositioned to above. Thanks Betty.

“The 2263’s secondary LCD is mounted on a rotating, extendable arm, which lets you move it from the side to the top of the main 22-inch screen in either portrait or landscape orientation,”
According to the review on Engadget ( http://www.engadget.com/2008/01/07/hands-on-with-the-samsung-2263dx-22-7-ubisync-lcd/ )
Thank you for the heads-up Betty, Engadget had a nice collection of photos showing how the arm is attached.