1. Convince Guido to give python 1.6 registry access in the core. I'm currently working on such a module.
Sure. Mail it to me ASAP. You'll also have to snail-mail me a wet signature on the conbtribution release form: http://www.python.org/1.5/wetsign.html. (I apologize for this sillyness, our lawyers require it and who am I to argue with them...)
2. (>=1.6) Use the registry to find Path, Include, and Lib directories for VC, and supply them on the command line.
3. (<1.6) Try to import win32api and win32con, and use Robins code to find the directories. If this also fails, inform the user that the environment must be set up for VC by running vcvars32.bat, and restarting setup.py. Note that it also may be possible the VC is not installed at all!
Or the wrong version. --Guido van Rossum (home page: http://www.python.org/~guido/)