Multiple monitor workstations have become common place for high-end graphic design applications. Below are several powerful systems and their applications. More to come!
9X media offers a full line on dual processor/multiple monitor workstations designed to handle all levels of CAD, CAM, software development, and other computer
Film
HDTV
Video
Visual Effects
Game Development
CAD
Architecture
Industrial Design
Scientific Visualization
SGI
Multiple Monitor Support - GNOME supports multiple monitors for applications, an important consideration in applications where screen real estate is critical such as medical imaging and seismic data processing. GNOME supports the Xinerama mode, enabling a panoramic view display of a single image across up to twelve monitors.
Link to 9X Media. Sponser of the Multiple Monitors.org site

Link to 9X Media site Link to Multimon