While on the topic, it would be really nice if we could associate SSH keys with user accounts, then use those instead of passwords. I've got diamond support with around 20 other people who can open tickets. The username is shared between all tickets, so the credentials are constantly getting reset when somebody has to upload files for another ticket. It's incredibly frustrating, and key-based authentication would skip this problem entirely.
GitHub does some fascinating stuff with GLB and repositories internally which involves pinning the SSH keys to repositories rather than to users. When cloning a repo from GitHub via SSH, everybody connects with the user 'git', but you can only access private repos if you authenticated with a key which has read access to that repo. That seems like it would be ideal.