It would take a lot of coding or hacking or some guff to the games to get them to do what you want them to do. But you have to remember there is a primary and secondary monitor mode for a reason. This means short of actually changing the games script you will not get it to run on the secondary monitor. I believe I once seen a game with this option but I think that game was crap… Anyway why the hell do you want to have a monitor displaying crap when you are trying to run a game, you will cripple your FPS.
Oh there is one use for this though, I remember when I was going through my WOW phase (what a waste of life). I used my secondary monitor, which was a 32” TV to watch movies on while I played WOW on my main monitor. The game had to be run in window mode or the secondary monitor would not work correctly.