Instead of Feedwordpress and Planet Planet put together with sticky tape and glue, I'm using the better documented Planet Venus and WP-Venus so our archives are maintained.
If you ever need to run a site similar to Processing Blogs and your web host can run python then I definitely recommend Planet or Planet Venus as the solution. WP-Venus complained a little bit when I converted from Feedwordpress, but it looks good so far: hopefully the archives will be worth the effort.