I just got an email from Matrox, makers of graphics solutions for professionals, about a new product they have announced. The DualHead2Go is a small external device that adds support for a third monitor for notebook computers (although it will work with desktops, too). The operating system treats the two monitors connected to the DualHead2Go as a single monitor running at resolutions twice as wide as each individual monitor. This makes it a pretty useful addition for anyone doing big graphic work like CAD and GIS. $169.