Any examples of adding custom fields to the category editor?

No. You have to use wp_options, because you can’t create new fields in the wp_term_taxonomy table (If you do, in the next WP update you’ll loose them).

So:

// the option name
define('MY_CATEGORY_FIELDS', 'my_category_fields_option');

// your fields (the form)
add_filter('edit_category_form', 'my_category_fields');
function my_category_fields($tag) {
    $tag_extra_fields = get_option(MY_CATEGORY_FIELDS);

    ?>

<table class="form-table">
        <tr class="form-field">
            <th scope="row" valign="top"><label for="_ce4-categoryTitle">Full Category Title</label></th>
            <td><input name="_ce4-categoryTitle" id="_ce4-categoryTitle" type="text" size="40" aria-required="false" value="<?php echo $tag_extra_fields[$tag->term_id]['my_title']; ?>" />
            <p class="description">The title is optional but will be used in place of the name on the home page category index.</p></td>
        </tr>
        <tr class="form-field">
            <th scope="row" valign="top"><label for="_ce4_fullDescription">Full Category Text for Landing Page</label></th>
            <td><textarea style="height:70px; width:100%;margin-left:-5px;" name="_ce4_fullDescription" id="_ce4_fullDescription"><?php  echo $tag_extra_fields[$tag->term_id]['my_description']; ?></textarea>
            <p class="description">This text will appear on the category landing page when viewing all articles in a category. The image, you supply above, if any, will be used here and this content will wrap around it.</p></td>
        </tr>
</table>

    <?php
}


// when the form gets submitted, and the category gets updated (in your case the option will get updated with the values of your custom fields above
add_filter('edited_terms', 'update_my_category_fields');
function update_my_category_fields($term_id) {
  if($_POST['taxonomy'] == 'category'):
    $tag_extra_fields = get_option(MY_CATEGORY_FIELDS);
    $tag_extra_fields[$term_id]['my_title'] = strip_tags($_POST['_ce4-categoryTitle']);
    $tag_extra_fields[$term_id]['my_description'] = strip_tags($_POST['_ce4_fullDescription']);
    update_option(MY_CATEGORY_FIELDS, $tag_extra_fields);
  endif;
}


// when a category is removed
add_filter('deleted_term_taxonomy', 'remove_my_category_fields');
function remove_my_category_fields($term_id) {
  if($_POST['taxonomy'] == 'category'):
    $tag_extra_fields = get_option(MY_CATEGORY_FIELDS);
    unset($tag_extra_fields[$term_id]);
    update_option(MY_CATEGORY_FIELDS, $tag_extra_fields);
  endif;
}

There might be some category-related hooks for the last two, I didn’t search for them. I just adapted the code above from a old theme of mine in which the admin can attach a image to a custom taxonomy term…