Drupal 7: How to completely theme form (or webform)

template.php

<?php

require_once 'template.theme_webform.inc';

/**
 * Implements hook_preprocess_HOOK(), form.
 */
function web_preprocess_webform_form(&$variables) {
  if ($variables['form']['#form_id'] == 'webform_client_form_72') {
    $form = &$variables['form'];
    $variables['myform'] = new stdClass;
    $variables['myform']->name_title = $form['submitted']['name']['#title'];
    $variables['myform']->name_description = $form['submitted']['name']['#description'];
    $variables['myform']->email_title = $form['submitted']['email']['#title'];
    $variables['myform']->email_description = $form['submitted']['email']['#description'];
    $variables['myform']->message_title = $form['submitted']['message']['#title'];
    $variables['myform']->message_description = $form['submitted']['message']['#description'];
  }
}

/**
 * Implements hook_form_alter().
 */
function web_form_alter(&$form, &$form_state, $form_id) {
  if ($form_id == 'webform_client_form_72') {
    $form['#attributes']['class'][] = 'met_form';
    $form['#attributes']['class'][] = 'met_contact_form';
    $form['submitted']['name']['#attributes']['class'][] = 'met_half_input';
    $form['submitted']['name']['#attributes']['class'][] = 'met_no_input_margin';
    $form['submitted']['name']['#attributes']['class'][] = 'met_input_text';
    $form['submitted']['email']['#attributes']['class'][] = 'met_half_input';
    $form['submitted']['email']['#attributes']['class'][] = 'met_input_text';
    $form['submitted']['message']['#attributes']['class'][] = 'met_full_input';
    $form['submitted']['message']['#attributes']['class'][] = 'met_input_text';
    $form['submitted']['message']['#attributes']['class'][] = 'met_textarea';
    $form['actions']['submit']['#theme_wrappers'] = array('webform_client_form_72_button');
  }
}

/**
 * Implements hook_theme().
 */
function web_theme($existing, $type, $theme, $path) {
  return array(
    'webform_client_form_72_button' => array(
      'render element' => 'element',
    ),
  );
}

/**
 * Returns HTML for a button form element.
 *
 * Override.
 */
function web_webform_client_form_72_button($variables) {
  $element = $variables['element'];
  $element['#attributes']['type'] = 'submit';
  element_set_attributes($element, array('id', 'name', 'value'));

  $element['#attributes']['class'][] = 'form-' . $element['#button_type'];

  // changes: add classes
  $element['#attributes']['class'][] = 'btn';
  $element['#attributes']['class'][] = 'btn-primary';
  $element['#attributes']['class'][] = 'btn-xs';

  if (!empty($element['#attributes']['disabled'])) {
    $element['#attributes']['class'][] = 'form-button-disabled';
  }

  // changes: change <input/> to <button> $element['#value'] </button>
  return '<button' . drupal_attributes($element['#attributes']) . '>'. $element['#value'] .'</button>';
}

template.theme_webform.inc.php

<?php 

/**
 * Replacement for theme_form_element().
 *
 * Override.
 * Changes: just return $element['#children'];
 */
function web_webform_element($variables) {
  // Ensure defaults.
  $variables['element'] += array(
    '#title_display' => 'before',
  );

  $element = $variables['element'];

  // return only #children
  $output = '';
  $output .= $element['#children'];
  return $output;

  // All elements using this for display only are given the "display" type.
  if (isset($element['#format']) && $element['#format'] == 'html') {
    $type = 'display';
  }
  else {
    $type = (isset($element['#type']) && !in_array($element['#type'], array('markup', 'textfield', 'webform_email', 'webform_number'))) ? $element['#type'] : $element['#webform_component']['type'];
  }

  // Convert the parents array into a string, excluding the "submitted" wrapper.
  $nested_level = $element['#parents'][0] == 'submitted' ? 1 : 0;
  $parents = str_replace('_', '-', implode('--', array_slice($element['#parents'], $nested_level)));

  $wrapper_classes = array(
   'form-item',
   'webform-component',
   'webform-component-' . $type,
  );
  if (isset($element['#title_display']) && strcmp($element['#title_display'], 'inline') === 0) {
    $wrapper_classes[] = 'webform-container-inline';
  }
  $output = '<div class="' . implode(' ', $wrapper_classes) . '" id="webform-component-' . $parents . '">' . "\n";

  // If #title is not set, we don't display any label or required marker.
  if (!isset($element['#title'])) {
    $element['#title_display'] = 'none';
  }
  $prefix = isset($element['#field_prefix']) ? '<span class="field-prefix">' . _webform_filter_xss($element['#field_prefix']) . '</span> ' : '';
  $suffix = isset($element['#field_suffix']) ? ' <span class="field-suffix">' . _webform_filter_xss($element['#field_suffix']) . '</span>' : '';

  switch ($element['#title_display']) {
    case 'inline':
    case 'before':
    case 'invisible':
      $output .= ' ' . theme('form_element_label', $variables);
      $output .= ' ' . $prefix . $element['#children'] . $suffix . "\n";
      break;

    case 'after':
      $output .= ' ' . $prefix . $element['#children'] . $suffix;
      $output .= ' ' . theme('form_element_label', $variables) . "\n";
      break;

    case 'none':
    case 'attribute':
      // Output no label and no required marker, only the children.
      $output .= ' ' . $prefix . $element['#children'] . $suffix . "\n";
      break;
  }

  if (!empty($element['#description'])) {
    $output .= ' <div class="description">' . $element['#description'] . "</div>\n";
  }

  $output .= "</div>\n";

  return $output;
}

webform-form-72.tpl.php

<?php

/**
 * @file
 * Customize the display of a complete webform.
 *
 * @see web_preprocess_form() in template.php
 */
?>
<div class="met_half_input met_no_input_margin met_input_header">
  <h4><?php print $myform->name_title; ?></h4>
  <span class="met_color"><?php print $myform->name_description; ?></span>
</div>
<div class="met_half_input met_input_header">
  <h4><?php print $myform->email_title; ?></h4>
  <span class="met_color"><?php print $myform->email_description; ?></span>
</div>

<?php print drupal_render($form['submitted']['name']); ?>
<?php print drupal_render($form['submitted']['email']); ?>

<div class="met_half_input met_no_input_margin met_input_header">
  <h4><?php print $myform->message_title; ?></h4>
  <span class="met_color"><?php print $myform->message_description; ?></span>
</div>

<?php print drupal_render($form['submitted']['message']); ?>

<div class="met_contact_thank_you">TODO: We received your message!</div>

<?php print drupal_render_children($form); ?>