Here is a very partial implementation of the flexible box layout.
Base on the latest w3c recommendation http://www.w3.org/TR/css3-flexbox.
The properties supported are
justify : (start | end | center | spaceAround | spaceBetween )
align : (start | end | center | stretch)
grow : number
direction : (row | column)
The layout handler is decoupled from the cocos2d node and modifies only the position of the node.
Sprites, Labels, Menu items are easily layout-formatted at init or dynamically at anytime.
This a box-based layout engine:
I've posted the source at