I always wanted distraction free text editing like supported by WriteRoom – but using a powerful text editor I am used to, e.g. TextMate.
As you can see in the screenshots, I managed to get very close to this goal. I use BackDrop to hide the desktop, and I use a patched version of Megazoomer to hide the Mac OS X menu bar, the dock, and the current window's title bar. The patch was necessary because Megazoomer's normal behaviour is to maximize both width and height of the current window and maximizing the width of a text editor can be problematic. Therefore, I created a version of megazoomer that maximizes only the window's height. Thus, you can also put multiple editing windows beside each other as you can see in the second screenshot. I also changed the shortcut to megazoom a window to Cmd+Ctrl+Alt+M to make it more TextMate compatible. You can find my patched version of Megazoomer here (installation instructions included).