What you want to do sounds similiar to how I have my site set up. I have seperated the standard index.php into header and footer files so that I can make ‘static’ pages.
(Keep in mind I have tags in these that are specific to my site)
Header.php:
<?php
/* Don't remove this line. */
require('./wp-blog-header.php');
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "https://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="https://www.w3.org/1999/xhtml">
<head profile="https://gmpg.org/xfn/1">
<title><?php bloginfo('name'); ?><?php wp_title(); ?></title>
<meta http-equiv="Content-Type" content="text/html; charset=<?php bloginfo('charset'); ?>" />
<meta name="generator" content="WordPress <?php bloginfo('version'); ?>" /> <!-- leave this for stats -->
<style type="text/css" media="screen">
@import url( <?php echo get_settings('siteurl'); ?>/wp-layout.css );
</style>
<link rel="stylesheet" type="text/css" media="print" href="<?php echo get_settings('siteurl'); ?>/print.css" />
<link rel="alternate" type="application/rss+xml" title="RSS 2.0" href="<?php bloginfo('rss2_url'); ?>" />
<link rel="alternate" type="text/xml" title="RSS .92" href="<?php bloginfo('rss_url'); ?>" />
<link rel="alternate" type="application/atom+xml" title="Atom 0.3" href="<?php bloginfo('atom_url'); ?>" />
<link rel="pingback" href="<?php bloginfo('pingback_url'); ?>" />
<?php wp_get_archives('type=monthly&format=link'); ?>
<?php //comments_popup_script(); // off by default ?>
<?php wp_head(); ?>
</head>
<body>
<div id="rap">
<h1 id="header">"><?php bloginfo('name'); ?></h1>
<div id="content">
Footer.php:
</div>
<div id="menu">
<li id="categories"><?php _e('Categories:'); ?>
<li id="search">
<label for="s"><?php _e('Search:'); ?></label>
<form id="searchform" method="get" action="<?php echo $PHP_SELF; ?>">
<div>
<input type="text" name="s" id="s" size="15" />
<input type="submit" name="submit" value="<?php _e('Search'); ?>" />
</div>
</form>
<li id="archives"><?php _e('Archives:'); ?>
<?php wp_get_archives('type=monthly'); ?>
<li id="calendar">
<?php get_calendar(); ?>
<li id="other"><?php _e('Other:'); ?>
<li id="meta"><?php _e('Meta:'); ?>
</div>
</div>
</body>
</html>
And then any page I want to create is only 3 lines of code:
Index.php:
<?php include('wp-includes/header.php') ?>
<?php include('wp-includes/posts.php') ?>
<?php include('wp-includes/footer.php') ?>
My resume and links page use this method.
You could create a new page: newpage.php
and have the code:
<?php include('wp-includes/header.php') ?>
<?php include('wp-includes/NEWTEMPLATE.php') ?>
<?php include('wp-includes/footer.php') ?>
If you want a completely different look for that page, just create a new header file and use a different CSS file for it.
<?php include('wp-includes/NEWHEADER.php') ?>
<?php include('wp-includes/NEWTEMPLATE.php') ?>
<?php include('wp-includes/footer.php') ?>
Create whatever CSS you want for NEWHEADER.php