I notice from the code that the plugin can have "extra" Google Analytics code added (Presumably via the config page of the plugin?).
# Add any tracking code before the trackPageview if ( '' != $extra ) echo " $extra\n";
However, what I'd like to be able to do is add extra code via a plugin. Would it be possible to add a hook in here that other plugins can use to insert additional Google Analytics code (For example segmentation data via _setVar).