Posts by user for date window?

[Abunch]

Other than a custom SQL query (I've got no problems coming up with one of those if I must), is there a way in the control panel to run a report that lists total # of posts by user over the past X days (or within a specific date range)?

Then I'd also like to know if there's a way to on a user's profile page (or somewhere that makes sense) show the user that same number.

I want to run post contests periodically - make a minimum of X posts in the next X days/weeks and we'll put your name in a drawing for whatever. This is easy to do when they're a new user that just signed up, but will become more difficult to track as time goes on if I can't find an automated way to do it.

Thanks!
Al