Thank you, @daninabil, that does the trick. Only works with posts that have manual excerpts generated -- I believe this is because it's outside the loop and we can't use get_the_excerpt, but something in the back of my mind says it could be a theme issue -- but this definitely works.
In case someone wants to use excerpts, here are the mods I used:
Line 218:
// A direct query is used instead of get_posts() for memory reasons
$rawposts = $wpdb->get_results( "SELECT ID, post_date, post_date_gmt, post_excerpt, comment_status, comment_count FROM $wpdb->posts WHERE post_status = 'publish' AND post_type = 'post' AND post_password = ''" );
Instead of modifying line 288, I modified line 295 (for visual/style reasons):
$html .= ' <br /><p style="padding-left:15px;">' . $post->post_excerpt . "</li>\n";