Apache Solr View Modes Module

<?php

/**
 * Implementation of hook_form_alter()
 */
function apachesolr_search_view_modes_form_alter(&$form, &$form_state, $form_id){

  /**
   * Override the Apache Solr Search Page configuration form
   */
  if ($form_id == 'apachesolr_search_page_settings_form'){

    $view_modes = array('' => 'Use default core search result');

    $entity_info = entity_get_info('node');

    /**
     * Build the view modes dropdown list
     */
    foreach ($entity_info['view modes'] as $machine_name => $view_mode){
      $view_modes[$machine_name] = $view_mode['label'];
    }

    /**
     * Override form to add custom view modes dropdown
     */
    if ($view_modes){

      //Grab search page id
      $search_page_id = $form['search_page']['#value']->page_id;

      /**
       * Fetch currently save Solr view modes
       */
      $solr_view_modes =  variable_get('apachesolr_search_view_modes', '');

      $form['info']['page_title']['#weight'] = -2;

      $form['info']['apachesolr_search_view_mode'] = array(
        '#type' => 'select',
        '#title' => t('View Mode'),
        '#description' => t('Select another view mode in favor of the default search view mode.'),
        '#options' => $view_modes,
        '#weight' => -1,
        '#default_value' => isset($solr_view_modes[$search_page_id]) ? $solr_view_modes[$search_page_id] : '',
      );

      //Add custom submit handler
      $form['#submit'][] = 'apachesolr_search_view_modes_save_view_mode';
    }
  }
}

/**
 * Apache Solr Save View Mode Form Submit Handler
 */
function apachesolr_search_view_modes_save_view_mode($form, &$form_state){

  //Get Solr View Modes
  $solr_view_modes =  variable_get('apachesolr_search_view_modes', '');

  $values = $form_state['values'];

  //Set View Modes
  $solr_view_modes[$values['page_id']] = $values['apachesolr_search_view_mode'];

  //Save Apache Solr View Modes
  variable_set('apachesolr_search_view_modes', $solr_view_modes);
}

/**
 * Implementation of hook_preprocess_search_results()
 */
function apachesolr_search_view_modes_preprocess_search_results(&$variables) {

  /**
   * This will override node results if a node view mode way selected on the apachesolr page
   * configuration page.
   */
  $solr_view_modes =  variable_get('apachesolr_search_view_modes', '');

  /**
   * Check to see if the search results page we are on has a view mode selected .
   */
  if (isset($variables['search_page']->page_id) AND isset($solr_view_modes[$variables['search_page']->page_id])){

    $view_mode = $solr_view_modes[$variables['search_page']->page_id];

    /**
     * Iterate through results and load the node view mode instead of the default search result
     * snippet.
     */
    if ($view_mode){
      //Reset Search Results, we are going to completely override
      $variables['search_results'] = '';

      foreach ($variables['results'] as $result) {
        if ($result['entity_type'] == 'node'){
          $node = node_load($result['node']->entity_id);
          $variables['search_results'] .= render(node_view($node, $view_mode));
        }
      }
    }
  }
}