I do many projects that require making polygonal hotspots. Flash editor is... a little bit annoying. So I wrote my own HTML5 polygonal editor (I've had only 20 minutes to do it). It's not perfect but some ideas can be helpful to other KRPano developers.
How it works? Press space (keyboard) to start drawing, then click (mouse) anywhere to set point. Finally, press ESC to stop drawing polygon. Feel free to use it and develop it. But remember - it's just ideas - not plugin. However... crowdfunding would be great idea to develop such plugins...