I have not been able to find much video at this high resolution, but I did find a blog run by a guy trying to make it. You 27" users should check out the video he made in fullscreen. It's not perfect, but it's a step in the right direction towards iMac super-HD 
Video:
http://vimeo.com/7464341
Blog:
http://joerodricks.posterous.com/a-short-time-lapse-2650x1440-video
Video:
http://vimeo.com/7464341
Blog:
http://joerodricks.posterous.com/a-short-time-lapse-2650x1440-video