Well, there is. It's called Yarf and allows you to select your From: line
depending on contents of message's headers. You can get it from:
http://www.vex.net/~x/files/yarf15.zip
___ _ _ _ _ ___
| . ) |/ / :::::::: Piotr K=EAplicz :::::::: \ \| ( . |
|__||_|\_\ http://rainbow.mimuw.edu.pl/~pkeplicz /_/|_||__|