Sure. It’s kinda long because I needed to translate the labels to Portuguese.

// Add custom taxonomy for Clients
add_filter('piklist_taxonomies', 'ceu_clientes');
function ceu_clientes($client_taxonomies) {
  $client_taxonomies[] = array(
    'post_type' => 'post'
    ,'name' => 'ceu_clientes'
    ,'show_admin_column' => true
    ,'configuration' => array(
      'hierarchical' => true
      ,'labels' => array(
        'name'                       => _x( 'Clientes', 'taxonomy general name' ),
        'singular_name'              => _x( 'Cliente', 'taxonomy singular name' ),
        'search_items'               => __( 'Buscar' ),
        'popular_items'              => __( 'Populares' ),
        'all_items'                  => __( 'Todos' ),
        'parent_item'                => __( 'Cliente pai' ),
        'parent_item_colon'          => __( 'Cliente pai:' ),
        'edit_item'                  => __( 'Editar' ),
        'update_item'                => __( 'Atualizar' ),
        'add_new_item'               => __( 'Adicionar novo' ),
        'new_item_name'              => __( 'Nome' ),
        'separate_items_with_commas' => __( 'Separe por vírgulas' ),
        'add_or_remove_items'        => __( 'Adicionar ou remover' ),
        'choose_from_most_used'      => __( 'Mais frequentes' ),
        'not_found'                  => __( 'Nenhum cliente encontrado.' ),
        'menu_name'                  => __( 'Clientes' ),
      )
      ,'show_ui' => true
      ,'show_tagcloud' => false
      ,'query_var' => true
      ,'rewrite' => array( 
        'slug' => 'cliente' 
      )
    )
  );
return $client_taxonomies;
}

// Add custom taxonomy for Colors
add_filter('piklist_taxonomies', 'ceu_colors');
function ceu_colors($color_taxonomies) {
  $color_taxonomies[] = array(
    'post_type' => 'post'
    ,'name' => 'ceu_colors'
    ,'show_admin_column' => true
    ,'hide_meta_box' => true
    ,'configuration' => array(
      'hierarchical' => false
      ,'labels' => array(
        'name'                       => _x( 'Cores', 'taxonomy general name' ),
        'singular_name'              => _x( 'Cor', 'taxonomy singular name' ),
        'search_items'               => __( 'Buscar' ),
        'popular_items'              => __( 'Populares' ),
        'all_items'                  => __( 'Todos' ),
        'parent_item'                => null,
        'parent_item_colon'          => null,
        'edit_item'                  => __( 'Editar' ),
        'update_item'                => __( 'Atualizar' ),
        'add_new_item'               => __( 'Adicionar nova' ),
        'new_item_name'              => __( 'Nome' ),
        'separate_items_with_commas' => __( 'Separe por vírgulas' ),
        'add_or_remove_items'        => __( 'Adicionar ou remover' ),
        'choose_from_most_used'      => __( 'Mais frequentes' ),
        'not_found'                  => __( 'Nenhuma cor encontrado.' ),
        'menu_name'                  => __( 'Cores' ),
      )
      ,'show_ui' => true
      ,'show_tagcloud' => false
      ,'query_var' => true
      ,'rewrite' => array( 
        'slug' => 'cor' 
      )
    )
  );
return $color_taxonomies;
}

Let me try to post once more, maybe today it will let me post.

I managed to solve my problem as I originally intended. The benefit my method brings is separating the hex color values from the client management, so that people that deal with entering data for clients/posts don’t need to deal with color values. I know my client long enough to know this is for the best, they are not very computer savvy. 🙂

There were a few things I needed to do to solve the problem. First, my Piklist files had a problem on the scope definition, by removing that I just let Piklist find the scope from where it was being created, which made sure all the variables would save correctly (they weren’t originally, as I found out).

The rest of the work was all on my theme file. The following is the code I used to pull the information from the database. Please note that I’m a designer, not a developer, so if there is anything about the code that makes you facepalm, please keep that in mind 🙂

<?php
  // Fetch the complete metadata object for ceu_clients
  $client_meta = get_the_terms( $post->ID, 'ceu_clientes' );

  // If a client was not set, skip trying to display the info box
  if ($client_meta && !is_wp_error( $client_meta )) {

    // Isolate the term_id for the client
    foreach ( $client_meta as $term ) { $client_ID = $term->term_id; break; }

    // Get the ceu_color ID for this client, and the HEX color value for the corresponding ceu_color
    $color_meta = piklist( get_term_custom, $client_ID );
    $color_value = piklist( get_term_custom, $color_meta[ceu_client_color] );
    ?>

    <?php // Set the CSS style for this client ?>
    <style type="text/css" media="screen">
      #post-<?php the_ID(); ?> .entry-side-meta .client a { background-color: <?php echo $color_value[ceu_hex_color]; ?>; }
    </style>

    <?php // Print the client information ?>
    <?php
    the_terms( $post->ID, 'ceu_clientes', '<div class="client">', '<br>', '</div>' );
  }; ?>

Took some effort, but I think the system works in a very elegant way for the user. Thanks a lot for the help.