Outputting to just an external monitor?

[slapple]

I've connected my 15" MBP (late 2011 running Lion) to the DVI input of my 24" LCD monitor, which has a resolution of 1920x1200. By default it turns my external monitor into an extended desktop. I see that I can also turn on mirroring, so that both the MBP and external monitor show the exact same thing. But my MBP runs in 1680x1050. Is there any way to have the MBP show the entire desktop on just the external monitor at 1920x1200?

 

[GGJstudios]

Apple Portables: How to use your computer in closed clamshell (display closed) mode with an external display

 

[slapple]

Thanks. The MBP definitely needs to be plugged in - it won't work on battery.