CSS overrides are nice but sometimes you need to alter your submit button to show up the same way in all browsers (yes, you IE!).

/**
* Alter search form to use image as background.
*/
function mytheme_search_theme_form($form) {
  $form['submit']['#type'] = 'image_button';
  $form['submit']['#src'] = drupal_get_path('theme', 'mytheme') .'/images/search_btn.gif';
  $output .= drupal_render($form);
  return $output;
}

Piece of cake!

Automated setupDon't get me wrong - I love Domain Access. I cannot however stand wasting time setting up a new (sub)domain. There are certain steps one can sometimes ignore - domain registration, server side configuration etc - if you happen to have people around to do it for you.