I hope I'm not stepping on anyones toes, but I made these icons today and I figured I'd share...
http://www.overwhelmed.org/pdicons/
The standard PD.app icon is too large for the cmd+tab application switching GUI, so I made some new ones. OS X icons can be up to 128x128 pixels, but I've noticed most restrict themselves to a smaller area and these icons take this into account.
Anthony