Creating another OpenGL window on 2nd screen (using video out cable)

[tatagogo]

Has anyone had any luck rendering OpenGL content on a 2nd display..? Most discussions/examples on the subject usually discuss mirroring existing content from the device's screen or displaying non-OpenGL content.

I know its certainly possible as there have been a number of games demonstrating exactly such functionality (Real Racing 2, Rage, etc) on supported iOS devices (iPhone4, iPad).. unfortunately there appears to be little documentation on actually doing this!

I'd greatly appreciate any wisdom that can be shared on this little problem!