Customise public board email address

The email-to-board functionality is great, but I want to be able to provide a “public” email address for client to log items. Whilst we can do this already with the “share outside this account” feature, the generated email address is not really good enough for public consumption. It would be great to be able to either customise this, just as we can with the mail address, or to select to say it should be the same.