Need-to-send-emails Notification

I have crap loads of draft emails in my draft box and keep forgetting to check them and send. Gmail (because that's what I use of course) should have a pop-up box type thing that prompts the person (sort of like the 'do you want to save this?' prompt) to set a time and date that they would like a notification for the particular email they were/are working on for future use. For example, I start to reply on an RSVP when I suddenly get called away from the computer. I haven't got time to finish it but need to send it before a certain date. So to make sure I don't forget, I ask Gmail to notify me in regards to this particular email if I haven't sent in by a particular date I set.

Comprende?

Now get cracking Gmail!