TotalThunderbirdConverter 4.1

Total Thunderbird Converter is designed to help you convert any of your emails to any of the supported formats. This allows you to archive important emails or just send some of them to anyone. Before converting the selected emails, you can change a few options for example the fields you want to include to the conversion (subject, sender, recipient, body etc.).
You can also include attachments in the conversion but please notice that this version can't convert attachments, you'll need the pro version if you want to perform this task. There is a great list of supported formats: DOC, PDF, HTML, TXT, and TIFF. To convert emails, you won't need to manually extract the Thunderbird database and send it to the program: it automatically detects Thunderbird installation and automatically retrieve the list of emails, allowing you to easily choose the e-mails you want to convert. If you are using a portable version of Thunderbird or the program can't find your database, you can manually open it using "File" -> "Open..." in the menu.
Bottom-line: this software is very great and will probably satisfy you. However, the price is rather stiff.