Another way would be to provide an init() method in your custom row class, to populate a member variable after the row is created.
Building on Davidoff's example:
PHP Code:
//custom row class
class UserRow extends Zend_Db_Table_Row_Abstract
{
public $fullname;
public function init()
{
$this->fullname = $this->forename . ' ' . $this->lastname;
}
}