hook_theme() should support 'file' and 'template' in different directories

If an uncaught exception is triggered on node/123, the maintenance page is displayed. If this happens in the admin section, I get the following error:
Warning: include(/home/chsc/www/drupal7/includes/maintenance-page.tpl.php): failed to open stream: No such file or directory in /home/chsc/www/drupal7/includes/theme.inc on line 1145

The reason is the following array returned by hook_theme() in the system module:

    'maintenance_page' => array(
      'arguments' => array('content' => NULL, 'show_blocks' => TRUE, 'show_messages' => TRUE),
      'template' => 'maintenance-page',
      'path' => 'includes',
      'file' => 'theme.maintenance.inc',
    ),

'path' indicates that the .inc file is in the includes directory. However, the default implementation of the template resides in system/module/maintenance-page.tpl.php, i.e. in another directory. Garland has its own version of maintenance-page.tpl.php, but Seven does not, and that is why it fails.

One solution is to simply move either the template file or the include file, but I guess it is reasonable enough to wish to have these files in two different directories.