Quote Originally Posted by Sonata Anthony
You simply can't keep it a secret; in the end, people have to know where to send the message. You can obfuscate for spam bots and just keep it private, but if you're sending someone a message, it's fair for them to have your address.

Your best bet would be to write a non-RFC compliant email sending application that specifically sends a false From: address.
I think that is true for the most part it is easy to recieve emails from another account with forwarding but it is dificult to alter who it is sent from. Unless you have some sort of server that takes your sent emails and proxys them... I suposed it is possible