As for 2): I believe that bdist_msi doesn't support upgrade installations currently, anyway. To support this, the UpgradeCode property would have to be specified. As it stands, multiple versions of the same PyPI package result in multiple separate installations (potentially overwriting each other's files).

It would be possible to automatically derive an UpgradeCode from the metadata, however, we would then still need to define what versions replace each other, and what versions can be installed side-by-side.

In any case, the name of the MSI file is irrelevant (AFAIK). They could be named the same or differently - what matters to Windows is the package code, the product code, and the upgrade code. The ProductVersion matters for the UI, and to determine whether something is an upgrade. See

http://msdn.microsoft.com/en-us/library/aa370859(v=vs.85).aspx