This is the section I suggest using
http://codex.wordpress.org/Category_Templates#Different_Text_on_Some_Category_Pages
It sounds like the only issue you have with that method is you’d like the content for each category description to be dynamic, so you can change it within the WordPress editor environment. You could do that by, instead of hard coding the description in the category.php template, by including the post or page content of another post or page within the category description area.
If you want to use pages, you will code the post ID# of each page you want included in the category.php template
Instead of this
<?php if (is_category('Category A')) { ?>
<p>This is the text to describe category A</p>
<?php } elseif (is_category('Category B')) { ?>
<p>This is the text to describe category B</p>
<?php } else { ?>
<p>This is some generic text to describe all other category pages,
I could be left blank</p>
<?php } ?>
something like this (this code likely needs tweaking and I made up the post ID #’s as examples):
<?php if (is_category('Category A')) { ?>
$page_id = 112; // post ID of page with Cat A descriptive text
$page_data = get_page( $page_id );
echo $page_data->post_content;
<?php } elseif (is_category('Category B')) { ?>
$page_id = 137; // post ID of page with Cat B descriptive text
$page_data = get_page( $page_id );
echo $page_data->post_content;
<?php } else { ?>
<p>This is some generic text to describe all other category pages,
It could be left blank</p>
<?php } ?>
That outputs raw page content. It may need to be run through WP filters. If you try this method and the content is not complete, post back here what is missing.
