Please note: Eudora still doesn't recognize utf-8, be
it in email content, subject or adresses... and it
probably never will...

And, of course, I have some customers that are still
using Eudora... :-)

I made the following patches:

+ in site-packages/roundup/rfc2822.py: 
- added an optional charset attribute to the
encode_header function, defaulting to utf-8:

  def encode_header(header, charset='utf-8')

and quote the message accordingly to the charset;

+ in $tracker/config.py:
- added an EMAIL_CHARSET option, that I set to
'iso-8859-1' where I want to keep compatibility with
Eudora;

+ in site-packages/roundup/roundupdb.py:
- in the IssueClass.send_message method, I convert the
content, subject and adresses from utf-8 to the
specified self.db.config.EMAIL_CHARSET option.