Recently I found Delink Pages 1.0 plugin by Jennifer Stuart. It promises something I was looking for:

This plugin will allow you to specify certain pages to not be linked when wp_list_pages() is used in a theme. You might want to do this if you want a header for a series of subpages, but don't specifically want that header to be a real page itself.

Instruction says:

To indicate that a page should not be linked when wp_list_pages() is used, edit the page that you do not want linked and create a custom field with a key of "delink" and value of "true".

Simple. Unfortunately it doesn't work. Below is the source code:

<?php
add_filter('wp_list_pages', 'scripty_de_link');

function scripty_de_link($output) {	
		$allpageids = get_posts(array('post_type' => 'page', 'numberposts' => -1));
		foreach ($allpageids as $eachpage) {
			//get custom field value for delink
			$delinkthis = get_post_meta($eachpage->ID, "delink");
			if ($delinkthis) { 
				$newurl = preg_quote(get_permalink($eachpage->ID));
				$output = preg_replace('@<a href="'.$newurl.'" (.*?)>(.*?)</a>@i', '$2', $output);
			}
		}
        return $output;
}
?>

So, what's wrong with this code? Apparently, parameters of preg_replace function are incorrect. I'm too old and too lazy to analyze the regular expression being used. Don't get me wrong. I love regular expressions but I wouldn't use them if there is a simpler solution. By adding one function ( str_replace_count ) and changing two lines of the original code I made it to serve my purpose. The new code follows:

<?php
add_filter('wp_list_pages', 'scripty_de_link');

function str_replace_count($find,$replace,$subject,$count)
{
   $subjectnew = $subject;
   $pos = strpos($subject,$find);
   if ($pos !== FALSE)
   {
     while ($pos !== FALSE)
     {
         $nC = $nC + 1;
         $temp = substr($subjectnew,$pos+strlen($find));
         $subjectnew = substr($subjectnew,0,$pos) . $replace . $temp;
         if ($nC >= $count)
         {
           break;
         }
         $pos = strpos($subjectnew,$find);
     } // closes the while loop
   } // closes the if
   return $subjectnew;
}

function scripty_de_link($output) {	
		$allpageids = get_posts(array('post_type' => 'page', 'numberposts' => -1));
		foreach ($allpageids as $eachpage) {
			//get custom field value for delink
			$delinkthis = get_post_meta($eachpage->ID, "delink");
			if ($delinkthis) { 
				$newurl = get_permalink($eachpage->ID);
				$output = str_replace_count($newurl, '#', $output, 1);
			}
		}
        return $output;
}
?>

It does not strip the page link entirely but replaces it with href="#" which causes no action when you click on it. You can see it implemented in one of my websites - synagoguefund.com. Top navigation bar was constructed with wp_list_pages. Three pages - History, Videos, and Donations are dummy pages acting as parents to meaningfull subpages.