Slightly inspired by Max for Ableton live, I've added Pd for Radium (Radium homepage: http://www.notam02.no/~kjetism/radium/)
Screenshot: http://folk.uio.no/ksvalast/radiumpd.png Video: http://folk.uio.no/ksvalast/radium_pd.ogv
It's basically got the same features as Max for Ableton, but I haven't implemented a modular note control system in Radium yet, so you can't, for instance, make an arpeggiator in Pd that controls other instruments. I will implement a modular note control system now though, because of Pd.
But at least it's possible to use Pd to make sound effects and soft synths.
It's a bit rough yet, so I haven't released anything. You must build Radium from source to get it, for now. It probably also only works on Linux. I haven't tried to compile on Windows or Osx yet.
To access pd, I have used libpd, but upgraded it to support several instances, gui, and pd-extended: https://github.com/kmatheussen/libpd