Quote from WinstonTJ:
I stopped at 6 and built another standalone machine with 4x monitors just because it got to be such a pain in the ass moving the mouse from one end to the other.
I think the idea of having multiple monitors is that they would provide all the information you need to look at during the trading session. User interaction (mouse, keyboard) is mimimal. Indeed it is hard to draw trendlines on all charts spreading over 12 monitors.
To help: 1) use a big trackball. 2) set the mouse speed in Windows to maximum. 3) Lay the grid in something like 2x3 instead of 1x6.