At 02:51 PM 6/15/2010 +0900, David Cournapeau wrote:

I am interested in doing this for arbitrary packages (the goal is to add support for egg <-> windows installer conversion in my packaging solution)

If your goal is to convert between eggs and bdist_wininst installers, you might want to take a look at the code that already exists in easy_install to convert bdist_wininst .exe files to .egg files -- even ones that weren't built by setuptools. Converting the other way should also be similarly straightforward, so I'm curious what this other metadata is that you're asking about.