Made the move to Loch Ness, and got some basic page grouping functionality working. TODO: fix some UI issues in Javascript ACL editor and change non-JS ACL editor to work with page groups too
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<script language="javascript" src="../../tiny_mce_popup.js"></script>
<script type="text/javascript" src="jscripts/embed.js"></script>
<title>Example of a custom preview page</title>
<link href="{$content_css}" rel="stylesheet" type="text/css" />
</head>
<body>
Editor contents: <br />
{$content}
</body>
</html>