Tiny 7" monitors that you can connect to your computer and power through USB:
These new MIMO displays from Korea’s Nanovision let you add a tiny 7″ LCD to your PC as a secondary monitor. Each mini-widescreen monitor features a sharp 800×480 display resolution, and can be rotated into landscape or portrait modes.Samsung also has a similar device that doubles as a digital photo frame.
Just connect the MIMO display to your computer’s USB 2.0 port, install the included software, and you’ll be up and running. You can even connect multiples to the same PC without need for any special video card. They each just show up as additional monitors under your Windows display properties.
The UM-710 model (98,000 KRW / $78 USD) is the basic version, while the UM-750 (183,000 KRW / $147 USD) adds a touchscreen, a built-in webcam and a DMB television tuner (perfect if you happen to watch TV in Korea).