The Polyphony guys hooked up 4 PS3s to display a quarter of a screen each to run Gran Turismo 5: Prologue at a resolution of 3840×2160 compared to its normal 1920 x 1080 display. They also had other units running the game 4 times as fast with a refresh rate of 240fps!

full write up can be found here;

http://www.gran-turismo.com/en/sp/d2788.html/ found via Kotaku