While an extremely cool feature - and don't get me wrong, I am behind you 100% - it would only be possible if they design the game in a very specific way. The reason you don't see many games that have multi-screen support is because you have to specifically instruct DirectX how to handle it. That being said, FFXIV has multi-screen support right now (as I understand it at least), so perhaps it indeed possible. Certainly if the game is capable of being displayed on all monitors, I don't see why this would be terribly difficult to write a mod for. Hmmm, I'll add it to my list I suppose.