We just normalized our user database and forms so that all emails are compared as lowercase. That means that Trac permissions and authentication will be case insensitive.
This makes things much easier and a bit less confusing. However, we were not able to get Apache’s authentication for Subversion to authenticate while ignoring case, which means for now you’ll be required to use lowercase emails when authenticating for Subversion. For most people this should be a non-issue since most emails aren’t mixed case, but for the rest of you, we hope this doesn’t inconvenience you too much. We may be asking you to break habit, but at the same time it’s less keys to press. ; )
If it becomes that big of an issue, we can start hacking Apache modules. But we’d rather focus on more important issues in this infrastructure phase, like migrating all your data to a replicated PostgreSQL database and getting Trac off CGI onto tracd clusters.