I'm almost attracted enough to the problem to make one. The users of my app have the same problem (usually) of having a limit of how many email messages can go out at a specific amount of time.

I could build this queueing system into my current app, but that would make the current app even more complex (safe to say, *its complex*) and having it completely separate would make it much more useful for other people.

We'll see :) If a backer of the project comes up... :)