Just a quick note:
Correct me if I'm wrong, but it seems to me that you (and some other people) don't distinguish between tooling for accommodating multiple versions of packages and actually supporting these packages.
To me, these are very different aspects - should RPM/YUM be able to support multiple parallel versions without the naming hacks? Yes. Should Fedora as a distro support numbers of multiple versions of packages? In my opinion, we should try to keep counts of supported packages minimal, as we do now. But that doesn't really depend on _how_ we package the stuff.
This is about providing the tooling to people who actually want to maintain these more versions in their private repositories or whatever.