I think an initial version of a pip gui need only install to the Python version running it.

The py launcher must discover some version of 'all' Python installs to choose, for instance, the latest 3.x version.  I do not know the details, nor which system py.exe runs on.  I was suggesting looking into the details after a first version.

A few days ago Steve Dower reported on pydev list how PSF installs on Windows register themselves in the registry (the keys used).  He also proposed a standard convention for other distributions to register, if they wish be be discovered by other apps, in a way that does not interfere with the entries for PSF installations.

Upendra, are you an intended GSOC student or simply a volunteer?  I am asking because, in the absence of submissions in nearly a year, I proposed on core-mentorship that this might be a good GSOC project.  I will not reserve this for GSOC if someone else is actually going to submit something.  But I also do not want to withdraw the idea unless someone is.