This plugin enhances the AdminBar and adds links to development, staging and live version of your website, furthermore it allows you to choose a color scheme of your AdminBar for all users on a website, including the frontend.
You also have to option to control the robots.txt visibility settings, in the newest version you get a watermark for posts that are in draft or scheduled, and a keyboard shortcut to hide the adminbar.
If you want to participate in the development head over to GitHub!
Screenshots
The basic idea of the plugin, 3 instances of a website, with 3 distinct color schemes and quicklinks between the instances.
The Adminbar on the frontend, showing the info panel on the right and the watermark for a draft post. The info panel can be hidden with a click. And there are keyboard shortcuts to hide the whole adminbar and the watermark to see what the site looks like for a regular user.
The settings page, with the options for the first of the 3 default stages.
The import and export function on the settings page.
The settings page when the settings are set using the filter add_filter( 'apermo-adminbar-sites', 'sites_filter' );