Converting email addresses between Unicode and ASCII is non 
trivial, as three different encodings are used (RFC2047, IDNA and 
ASCII). Here is an EmailAddress I use and a test suite, which I feel 
should be integrated into the email package. I'm quite happy to 
implement a different interface if the 'unicode subclass' design is 
unsuitable, although I got no feedback from the Email-SIG so they 
are either happy with it or asleep ;)