Add region-based suggestions for bean blocks (Drupal 7, bean module)

template.php

<?php
/**
 * Implements hook_preprocess_block()
 *
 * For each bean block, add a template suggestion containing the name of the
 * region where the block will appear.
 *
 * Requires "bean" module (fieldable blocks)
 */
function THEME_preprocess_entity(&$vars, $hook) {
  if ($vars['entity_type'] == 'bean') {
    if (isset($vars['elements']['#block'])) {
      $region = $vars['elements']['#block']->region;
      if ($region) {
        $new_suggestions = array();

        // Regions are usually lowercase and don't contain dashes, but it can't
        // hurt to be sure.
        $lc_region = str_replace('-', '_', strtolower($region));
        $new_suggestions[] = $hook . '__region_' . $lc_region;
        foreach ($vars['theme_hook_suggestions'] as $suggestion) {
          $new_suggestions[] = $suggestion;
          $new_suggestions[] = $suggestion . '__region_' . $lc_region;
        }
        $vars['theme_hook_suggestions'] = $new_suggestions;
      }
    }
  }
}