Bring up the Subject is a small plug-in for Mail.app that changes the main table to use a two-line display. This is intended to complement the Letterbox plug-in, which changes the message pane from horizontal to vertical.
Source Code Highlighting requires Mac OS X 10.5 Leopard. It has been tested on Mac OS X 10.5.4 (Mail.app 3.3), but I expect it to work with any version of Mail included since 10.5.0. After decompressing, move Bring up the Subject.mailbundle to ~/Library/Mail/Bundles.
The source code is freely available at GitHub. Please send Jonathon Mah an e-mail if you'd like to share your changes.
Bring up the Subject is licensed under the BSD license, as follows:
Copyright © 2008, Jonathon Mah All rights reserved.
Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
This software is provided by the copyright holders and contributors “as is” and any express or implied warranties, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose are disclaimed. In no event shall the copyright owner or contributors be liable for any direct, indirect, incidental, special, exemplary, or consequential damages (including, but not limited to, procurement of substitute goods or services; loss of use, data, or profits; or business interruption) however caused and on any theory of liability, whether in contract, strict liability, or tort (including negligence or otherwise) arising in any way out of the use of this software, even if advised of the possibility of such damage.