Hi,
I'm trying to do the same thing. Yes it's more than just possible. The problem is very easy, but not simple to do.
If we can understand how the php can control, create, delate, ... forward,... etc. those domain emails via imap4 or pop3 system then we can do something like that very soon. Personaly I would be more then just happy if I could find a script that can do a redirection only for the subscribers. Or only for a pesonal use (controlled by one person only); just to learn how the code actually works on that base.
I'm interested in that project too. I'm willing to give my contribute with pleasure. If someone would like to join. Please do give us a hand to give a hard kick to a closed sorce socity.
-Gord