As inspired by http://www.reddit.com/r/SublimeText/comments/2i3p7q/til_option_to_highlight_active_scope_guide_line/ and many desires before it, I would like to be able to extend of top of existing themes in Sublime Text. To remedy this, I am proposing the following plugin.
Scrapes all installed themes, prompts user for theme to extend (starting with current at top), prompt user for theme name (default of 'Theme Extender - ' + current name), open blank page with comment explaining how to use.
Upon saving, copy theme, add new parameters, save to custom theme, and apply custom theme to user settings (if it hasn't been already).
List all existing extensions by name (current first, else alphabetical), open existing extension.
Upon saving, take same action as create.
List all existing extensions by name (current first, else alphabetical), give confirmation prompt to verify user wants to delete theme, revert to non-extended form or Monokai as default?
Optional command
Scrapes all installed themes, prompts user to select theme to view, open theme file in read-only format. This would be practical when extending a new theme.