Subscriber Email Plugin – Advanced Features?

Hey guys,

Was wondering if anyone has heard of, or are using a Email Subscriber Plugin, something that will track users who subscribe to the site. I currently am using G Lock Double Opt In at the moment and it works great. My client however wants a custom promotion attached to the Welcome email after the user has confirmed their subscription. I was wondering if anyone has come across this before?

My problem seems to be, if I just put in a download link in the welcome email, some douche of a clients, can go back to the download link and rip off the company. I would hate for that to happen.

Any insight as to what to do, recommendations, or even a plugin coming close to, would help. I’ve searched for a quite a while until I found myself going in circles of things I’ve already looked at.

Thanks in Advanced.

-B00m