This plugins gives you a number of different options for controlling your admin bar. You can allow certain users to see or not see the bar based on user roles. You can disable the admin bar on a single page or sitewide. And you can also use CSS to change a number of different styling options for the bar.
WPMU DEV Custom Admin Text WordPress Plugin 2.0.3.1
WPMU DEV Recent Global Posts Widget 3.0.6
WPMU DEV Custom Admin Bar WordPress Plugin 1.3.2
