I'm looking for a MTA for windows, that can simply receive an email, and then invoke a program when it does, whit the email as it's parameters. Simply put: The server receives an email, than calls the program "handleemail.exe", passes it the email (as parameters or trough some other means), and finally exits. So the email isn't stored anywhere unless actually handleemail.exe chooses to do so.
Turns out hMailServer fills my needs. I can hook in and interrupt the delivering of the email to the local user, and then pass it on to my own program/script.