The answer is very simple, in fact… there’s a user style that will hide all extra statusbar items, while keeping the regular Firefox items intact… until you move your mouse over the status bar, and then they all show again. Brilliant!
Installing Auto-Hide Style
To use this Stylish script, you’ll need to have the Stylish extension installed, then just click the “Load into Stylish” button on the user style page (links at the bottom).
You’ll be asked to save the style, and immediately after installing, here’s the nice clean status bar…
It even still works as normal when you hover your mouse over a link:
But when you move your mouse over the status bar, then it shows your cluttered list of icons and whatnot:
It doesn’t work perfectly, but it does work pretty well with most extensions, and is now an indispensable part of my script library.
Removing Auto-Hide Style
To remove this, click on the Stylish icon and choose “Manage Styles” from the menu.
You can either remove the checkmark next to it, or just select it and click the Delete button.
Note: I tested this in both Firefox 2 and Firefox 3 beta 3
Download Stylish from Mozilla Add-ons
Download Statusbar “Mouseover for Clutter” User Style from userstyles.org