Very nice.
I like how much information the file names provide. Do you think it would be possible to add (optional) build numbers to the specification? At Enthought, we make a Python distribution with access to a repository of binary eggs. When regularly building third party eggs for downstream consumption, it's essential to have build numbers in the file name since we need to fix bugs in our builds while keeping the upstream version of the package itself the same. Linux distributions have the same issue and put in build numbers into their package file names.
Ok. Read the python versioning spec. Perhaps it can be extended, or delimited with another character besides -
I'm not sure I'd go so far as to force every .whl to have a build number in it, but it would be great if we could figure out a way to have a compatible convention that could include build numbers when needed.