LCD4WoW implements LCD4Linux displays in WoW. You can configure as many displays as you want, have certain displays have priority over other displays, add layouts, layers, widgets, etc... If you're not sure what LCD4WoW is, then I suggest you visit the LCD4Linux website. In short LCD4Linux controls hardware Liquid Crystal Displays, both character and graphical displays. It has a wide variety of hardware controllers - the actual interface to the hardware itself. It has an evaluator element for executing code, properties as a wrapper around the evaluator, and the other elements already listed.
LCD4Linux is written in C. I wrote a Cpp program named LCDControl that was based on LCD4LInux. I implemented practically the entire LCD4Linux C code into object oriented Cpp, allowing you to control as many displays as you want, and switch between layouts based on a timer. You can choose what transition options you want when changing layouts, and it has other enhanced widgets, such as histograms, GIF images, Big numbers, and a LibVisual widget for showing music visualizations on an LCD. It's written mainly for Linux, but I left room to implement a Windows version by making the plugins dynamically loadable, so you could compile Windows-only plugins if you wanted.
LCDs aren't as popular as they used to be, but I'm trying to change that by advertising LCDs in a WoW addon.