Mobile Monitor Technologies' Monitor2Go is an external display designed with the iPad in mind. Its physical design is much like a laptop; it has two parts attached by a hinge, with the external display on one side, and an iPad docking space on the other. You slip the iPad into the dock, connect the video cable to the iPad (an HDMI adapter is required), and then you access the iPad screen through a cutout on the device.
The company has two versions of the Monitor2Go. The $299 model has a 1366-by-768 resolution, while the $329 model (which made its debut at Macworld/iWorld has a 1500-by-900 resolution. Both screens measure 15.6 inches diagonally. Since the Monitor2Go uses HDMI, you can connect it to any device with HDMI out.