Drupal 7 appending class in uc attribute option radio button
I managed to get what I wanted  inside theme_uc_attribute_add_to_cart by using:

foreach (element_children($form) as $aid) {
     foreach (element_children($form[$aid]) as $option) {

        $form[$aid][$option]['#prefix'] = '&lt;div class="row single-double"&gt;';
        $form[$aid][$option]['#suffix'] = '&lt;/div&gt;';

      }
    }


But I really don't want to mess with uc_attribute.theme.inc is there any other way?