Jame Teh advised that

"Thought you might like to know that Mick recently discovered that you can actually set global keyboard and mouse hooks in pure Python using ctypes; i.e. without needing a dll or extension. NVDA has now switched to using this technique. The relevant modules are called keyHook.py and mouseHook.py in our svn."

That will simplify things and remove a dependency on external code (pyHook).