You can get a bit more real estate out of smaller screens in Mac OS X. The AppleDisplayScaleFactor can be used to scale down new windows that are opened. For example, they would be 70% of their original size using the following command:
defaults write -g AppleDisplayScaleFactor 0.7
You can tinker around with different scales and if you find one you like then you can set it permanently by adding it to the NSGlobalDomain:
defaults write NSGlobalDomain AppleDisplayScaleFactor 0.7
The default screen scale factor is 1.0 (.7 just makes things smaller), so in order to get the screen scaling back to normal just run the command substituting a 1.0 for a .7 as you can see here:
defaults write NSGlobalDomain AppleDisplayScaleFactor 1.0
