I believe that you can use both the ch.31 and post 911 GI Bill for PPL as long as you can find a school that offers it as part of a Bachelors or Associates degree. I will be doing this for the upcoming fall semester maybe summer. This flight school local to me partners with 3 community colleges in the area. They all provide an associates degree in aviation science wich takes 2 years and includes PPL, CPL, and instrument rating.
I'm pretty sure you can use either forms of the GI Bill appoaching it this way since the flight labs are part of the curriculum.