I made this work by making the following changes, but I'm not sure what the repercussions might be...

In libraries/joomla/database/table/user.php:

[code:1] /*if ((trim($this->email) == ""«») || ! JMailHelper::isEmailAddress($this->email) ) {
* $this->setError( JText::_( 'WARNREG_MAIL' ) );
* return false;
*}
*/[/code:1]

AND:

[code:1] // check for existing email
$query = 'SELECT id'
. ' FROM #__users '
. ' WHERE email = '. $this->_db->Quote($this->email)
. ' AND id != '. (int) $this->id
;
$this->_db->setQuery( $query );
$xid = intval( $this->_db->loadResult() );
/*if ($xid && $xid != intval( $this->id )) {
* $this->setError( JText::_( 'WARNREG_EMAIL_INUSE' ) );
* return false;
*}
*/[/code:1]

Anything I should be worried about here?

Props man been trying to figure out how to do that for forever!!!! seems to be ok for now