Toolbar (Icons) Next To Tabs?

I mentioned over on the Firefox Blog about a thread in the Thunderbird Builds forum asking if there is a possibility of being able to have toolbar (icons) next to the tabs like in Firefox. They posted the following mockup of how they would like this to look in Thunderbird (note they are using Small Icons and have the ‘Show:’ setting as Icons):

At first I really didn’t understand what they were asking or why you want to do this. However, the more I got to looking at this, the more I would like to see this feature. This is a nice way to clean up wasted space in Thunderbird (especially just using ‘icons’ only) and provides a cleaner looking interface as well.

While nothing official has been posted there has been discussions in tb-planning about changing the UI in Thunderbird. However, given Thunderbird 5 has already reach the feature freeze point (of course technically so has Thunderbird 6 if they are following the Firefox release schedule) the earliest we could see this would be Thunderbird 7 or possibly Thunderbird 6?

I have not yet had a chance to take a look the pre-release version of Thunderbird 6 (if there is one yet) or the current Nightly builds which are 7.0. I’ll try to take a look these in the coming days to see what changes have been made.