You won't have to program a plugin for this, Conitec is already working on this!
Read the forecast-document:
quote:

WINDOWS CONTROL ELEMENTS (priority: low)
Allows to create arbitrary Windows applications by providing a C-Script
interface for creating windows and applying styles, buttons, and menus.

Unfortunately, the priority is low, so you will have to wait a little bit. But, I suppose it would take more time if you try it by yourself or use a panel-solution.