Because it's difficult enough having to explain it, I've gone ahead and modified the default (Kubrick 1.5) theme to provide a sidebar at all times:
http://guff.szub.net/wp-content/default_allsidebar.zip
To use, unzip to the directory/folder "default_allsidebar", upload this to your wp-content/themes/ directory on your blog's site, and select "WP Default - AllSidebar Edition" under Presentation in WordPress.
Changes:
* Templates previously single-column reset to the 'narrowcolumn' id.
* <?php get_sidebar(); ?> added to those templates which lacked it.
* Reference in header.php to kubrickbgwide.jpg removed.
* A tiny bit of cleanup, clarification of comments.
I also slipped in the get_calendar() template tag, though it is commented out; to display it, remove the html comments from around it in sidebar.php.
Note: If this steps on any toes, so be it.
UPDATE: For those who want to display links and login info in your sidebar at all times as well, I've separately made available a modified version of this:
http://guff.szub.net/wp-content/kubrick_sidebar.zip
Extract sidebar.php from the zip and replace your current one (either in default or default_allsidebar) with it.