Multi-screen (FOREX) Trader PCs
Multi-screen systems - Digital Tigers
Digital Tigers produce an entire range of powerful multi-display computer systems and custom multi-display setups and solutions.
Multi-screen trading systems - existing equipment
If you already have a suitable PC, multiple displays and display adaptors then try VT MultiDisplay. I use VT MultiDisplay on my multi-display systems and love it. It's fast, easy and makes it very easy to set up keyboard shortcuts. Once you have multiple displays, you'll find that Windows XP's built-in multi-display support doesn't quite fit the bill - VT MultiDisplay fills the void.
Multi-screen trading systems for notebooks
Obviously you're not going to stuff a pile of PCI display cards in a laptop computer. However (assuming your laptop is powerful enough) there are viable solutions. VillageTronic offer a laptop PCI card with two video outputs. This gives a maximum possible screen set of four (two connected to the PCI card, the laptop display as one and a fourth connected to the back of the laptop - depending on your laptop's capabilities).
Along with their custom multi-displays, Digital Tigers manufacture multiple solutions from dual-monitor