I'm willing to pay if you can create an add-on that provides the following functionality:
1. Disable the instant e-mails being sent whenever someone responds to a thread.
2. Replace the instant mails with a daily or weekly digest.
3. The mails should contain a list of topics that the user is subscribed to and have been responded to since the user last read them.
4. The user should have the option to receive the digest once a day or once a week (with no mails being sent if no new posts are made).
5. The template for the e-mail should, if at all possible, be customizable since I will probably need to translate some things.
If you are interested please contact me so we can talk in detail about payment and requirements of the add-on.