Send to Multiple Email Addresses from Form Field, separated by commas

Hi, this is what I would like to do, taken from http://drupal.stackexchange.com/questions/5754/webform-send-multiple-email:

I have created a webform. There is one field "Send invitation to your friends" . In this field user can enter their friends email ids (Comma seperated) For example A@gmail.com,B@yahoo.com,C@hotmail.com etc. I want to send a common email "Welcome and join us" to all these people. Can anyone help me, how can I proceed?

And here are a few hurdles I am finding:

1. To send to an email a field must be of type "email", however the markup that is generated does not have the "multiple" option applied, so modern browsers will invalidate anything separated by commas, such as "A@gmail.com,B@yahoo.com,C@hotmail.com". Therefore a "multiple" checkbox would need to be added to the email component creation form that would add this attribute to the form element when checked.

2. The email component validation function does not expect emails to be separated by commas and checks the value against Drupal's validate_email function with the whole value of the field:

function _webform_validate_email($form_element, &$form_state) {
  $component = $form_element['#webform_component'];
  $value = trim($form_element['#value']);
  if ($value !== '' && !valid_email_address($value)) {
    form_error($form_element, t('%value is not a valid email address.', array('%value' => $value)));
  }
  else {
    form_set_value($form_element, $value, $form_state);
  }
}

This function would need to check if the multiple flag is set to true on the form_element and validate accordingly (separate by delimiter, trim and validate each item separately).

3. I tried using a regular text field and token value [submission:values:emails_to_share_with] in the "Custom" box when setting up an Email item, but it also tried to validate assuming an email value or a separation of email values, giving the error:

The entered e-mail address "[submission:values:emails_to_share_with]" does not appear valid.

so this is not a viable workaround.

Is this a feature that exists, or is there a known workaround? I have searched but found nothing quite fitting the requirements. If it is not a feature and it seems like something that would be useful, I wouldn't mind helping to develop a patch for it if it would be helpful?