A cheap and simple way to remove the gray bar is to simply edit /wp-admin/css/colors-fresh.css. Search for: #wphead, body.login and change the color to white (#ffffff) or transparent.
Also, you shouldn’t have lost the logout message. I’d upload a fresh copy of wp-admin.php and try it again.
As far as I know, you only have to remove the last two instances of: <p id="backtoblog"><a>/" title="<?php _e('Are you lost?') ?>"><?php printf(__('« Back to%s'), get_bloginfo('title', 'display' )); ?></a>
The second one is for the register screen and the third is for the login screen. Not sure what the first one is for, but editing it is probably what broke your logout message…
