Thanks to some discussion over at the ADF Methodology Group and contributions from Simon Lessard and Jan Vervecken I have been able to make some refinements to the Task Flow Design Fundamentals paper on OTN.
As a bonus, whilst I was making some edits anyway I've included some of Frank Nimphius's memory scope diagrams which are a really useful tool for understanding how request, view, backingBean and pageFlow scopes all fit together.