LIIP has an example of fine-grained subversion commit emails, where email recipients are under the control of anyone who has write access to that part of the repository. However the resulting emails themselves aren’t as nice as those from some other packages, e.g., the commitmessage-2.0 stuff described below.
LIIP-style configuration is preferable to, e.g., commitmessage-2.0, where commit emails are under the control of a configuration file on the SVN server, thereby requiring the administrator to intervene every time a user wants to change who gets emails.
IST at Berkeley has some very useful SVN tips regarding their configuration, which uses a “metadata repository” of sorts to store information about access control, etc. I hope to look into it as well to perhaps also eliminate the need for users to have a login on the server to manage access to their repositories.