I made a patch for controlling the PushPin interface from Max/MSP. The patch isn't finished, but I have decided to make this version available. The controls are rather self explanatory. The file that you want to open is 3P.pat after you unzip the archive. This will run in Max/MSP or the Max/MSP environment. The environment can be downloaded for free from the Cycling74 website for a number of platforms.
You can download this patch here: http://milkcrate.com.au/_other/downloads/projects/3P/
I currently don't have an environment in which I can successfully test a VST made from this Max/MSP patch, because MIDI output is not supported from a third-party plugin in both ProTools and Live. Once I get around to testing such a plugin, I will make a VST that is based on this Max/MSP patch available.