i created a new test page and a new test template and copied the template file and called it "test.php". on this file i added on top
$page = $pages->get("name=original")
and on header and footer, where i had things like
if($page->template == "original")i had to change them to
if($page->template == "original" || $page->template == "test")
All works fine, of course, but i was thinking that maybe all this could be made easier with a module. Would be nice if, for instance, the system would recognize a specific URL parameter (site/page/super-secret-test-parameter), and look for the file "test_template.php" instead of "template.php". I don't have any idea of how to make a module like this that's why I'm posting it here.