As Jens wrote a while ago, we are looking into customizing Qt Quick for use on the desktop. In one of the comments he also revealed that I'm working a Mac-specific project. Time to blog!
Toolbar in action : Nothing we haven't seen on Mac before, although the customize menu is new to Qt applications.
What is different from the current Qt solution? First of all, we're using NSToolBar instead of QToolBar, which means we get the correct native look and feel (including the desired customization menu) for free. Second, the toolbar can be created just like any other QML item:
text : "Button 1"
iconSource : "images/qtlogo.png"
toolTip : "This is button number 1"
onActivated : status.text = "Button1 Clicked"