Thus far, after playing with the add-on in question, I think anywhere from 40 to 50 is a good minimum tab width.  You could go all the way down to 1 though if you really wanted to (however, this pretty much makes the tab bar impossible to use). So why is this so exciting to the masses?  Well,  you used to be able to make this tweak in your about:config settings – however it appears that in Firefox 4 they took this feature out and moved it into the theme’s settings (to give more customization features to theme designers).

Want to pick up Custom Tab Width? You can do so by download it from the Firefox Add-ons website.

Here is a little more about Slickerfox from it’s creator:

There is a philosophy behind the shapes, colors and designs of all of the Slickerfox icons, which aspires to be user friendly as well as recall older Firefox designs. Simplicity and intuitive control is the overall goal of the theme. Slickerfox uses native OS Scheme settings just like the default Firefox theme, so it will follow the look of the rest of your OS.

Like what you see?  You can pick up the experimental theme, Slickerfox for Firefox from the Firefox Add-ons web site.

Firesizer is an extension for Firefox that will let you pre-set a series of browser sizes so you can quickly jump from one to the other. Here is a little more information about the extention:

Provides a menu and status bar to resize the window dimensions to a specific size. Unlike other similar extensions, this one sets the size of the *entire window*, not just the HTML area.

Nobody is going to claim this extension is reinventing the wheel, but it is a small extension that does what it sets out to do. As long as you can get that much done, your alright in my book.

After you install, right click on any toolbar and choose customize. Drag all items in the navigation toolbar (back/forward, address bar, etc) up into the menu bar. Right click on a toolbar again, and un-select the (now empty) navigation bar. Tada, tiny!

[Learn More About Tiny Menu!]