PyQtFlowLayout
The flow layout that many have shared from the given examples needs additional methods to become really useful, in particular, I needed it to be able to propagate up into a scrollable wrapper.
Example
Usage:
scroller = ScrollingFlowWidget()
scroller.addWidget( QtGui.QPushButton("Push Me") )
scroller.addWidget( QtGui.QPushButton("Don't push") )
...