Patko and I just got TkDND working on Windows and included Pd-extended 0.43. That means tomorrows nightly build should have it included, and its ready for scripting with. TkDND allows Pd to handle drag-n-drop events, so you can do things like drop a file onto the Pd window to open it (implemented in the attached plugin) or drop a pd patch onto a canvas to make an object (also kind of implemented in the plugin).
There are lots of interesting ideas possible, I'm hoping you will play with it and see what kinds of stuff we can do. I forgot who originally implemented the TkDND stuff for Pd, but this is based on that work, so thanks for that.
.hc