Hey there! Any changes regarding “There isn’t a filter built-in to the theme for this.” ? I’d love to have such filter. Don’t want to use a plugin just to have a 404 page.
yes, the new generate_do_template_part() function will allow users to ‘hook’ in there own content for any of the theme templates. Currently that will require code, in the near future you will be able to use the Elements module to do it.