Cool, but I still think tabs should be as wide as the window when not stacked. Small tabs only make hitting them harder.
Protip (sorry for using the term), stop using the titlebar to move Windows. I feel physically encumbered when using Windows or OS X because I can't Alt+Drag windows around. It will make you so much faster because you just hold Alt and click and drag. No more searching for that tiny little microscopic bit of window to drag. (For example, Chrome on OS X has almost NO hit space to drag the window). I guess this post is sorta useless if you don't use Linux, but take it for what it's worth I guess.
I have given up on windows. Most of the time mine are maximized and I switch spaces instead.
I can't bring myself to do that on a 15.4" screen (I like the real estate specifically for multitasking and looking back and forth) but I've seen it leveraged extremely well on a 11/13" Air.