Someone may find this useful. I finally found the time to ditch thunderbird and configure mutt and imapfilter. Fully inaccurate write up at:
http://ericholzbach.net/blog/2011/07/using-mutt-with-imap-and-imapfilter-on-freebsd/
http://ericholzbach.net/blog/2011/07/using-mutt-with-imap-and-imapfilter-on-freebsd/