"All you need to do is to send emails to us." - no thanks. If you've built something more sophisticated than I can implement with Perl and Exim's system filter

"All you need to do is to send emails to us." - no thanks. If you've built something more sophisticated than I can implement with Perl and Exim's system filter functionality, I might be interested in giving you money to save me my time. Maybe a per-domain license?