Webform is essentially a node. $message variable is rendered in page.tpl.php and it outputs all messages (errors, status, warnings). If you don't have anything else on the page but your form, and you don't mind outputting all kinds of messages that may appear on the page under your submit button, then - overriding page template for that one form might work.
You would create a page--node--nodeID.tpl.php. Move $message variable below $content variable. Clear cache. This is a quick but not a very elegant approach.