Set a theme for a single content types edit page
Using hook_menu_alter you can override even the theme a path uses.

function hook_menu_alter( &amp;$items)
{
    $items['path']['theme callback'] = 'variable_get';
    $items['path']['theme arguments'] = array('theme_default');
}


like this you set the theme for that path to whatever the user theme is, even for admins.