I actually have my application running on the macZOT promo as we speak,
It's set up so that macZOT queries a page with a name, email and order number. This generates an order in the Potion Store database, emails the license back to the user, and returns the license key to macZOT. It marks the method of payment as maczot in the database.
The big caveat being that it's really a crude hack I threw together Wednesday night. It's the first time I've ever written anything in Ruby and I was literally reading my first tutorials on ruby and rails while throwing this together. So, I'm happy to send you my code, but I didn't think it was worthy of committing back (yet).
Jeffrey