That's an interesting idea, but if people notice the e-mail address they might be hesitant to respond.

From what I've read, there's a delagate option that allows a user to send an email on behalf of someone else without the "on behalf of" phrase. I'm not sure how to set this up though. One site I read said that if I had complete access to an Inbox, then I could send e-mails as if I were my manager.