I was thinking of adding a new kind of command button for launchbars, a "Toggled App" button.
It would work like this:
You set up a button for an application, let's say "Firefox.exe".
When you press the button, LBC would start firefox if it's not already running, or terminate it if it is already running.
We would probably want some kind of option to change the way the button looks based on whether it's running or not.. Like gray out the icon if it's (not) running..
Useful or no? I suppose that, except for the graying out, one could already do this by using a standalone commandline utility to run or terminate another executable based on whether it's already running (that's a nice idea for a little coding snack).