Terminal command to create 'To Do' items through Mail.app

Terminal command to create 'To Do' items through Mail.app

I've been dorking out with GeekTool and like my simple geeklet that
displays my uncompleted tasks right on my desktop. I made a service with
automator to let me create new To Do's in iCal whenever activate my
shortcut to it. The 'problem' if you can call it that, is that I don't
like having extra apps open. I rarely use iCal but Mail.app I use
frequently so it's always open.
What I want is some script that will create a new To Do through Mail so
that I can put it in a service and call it up from anywhere using a
keyboard shortcut. That way I won't have to open iCal when I add to do's.
Yes I'm aware that there's already a shortcut to create a new to do in
Mail, but I want to be able to make to do's wherever I am.
Is this frivolous? You betcha. But I like workflow solutions that will
save me maybe 5 minutes over the course of ten years.