I came here to make sure the above comment was already visible, but I also sat and thought for a moment. What would be the real solution versus "invent + 1" solution too...
What about a layer that interacted with each local package manager? Basically an easily installed wrapper for any native package manager. It wouldn't do everything the native managers did, but it could offer synonyms between them (RPM names = DEB names) to let people use the terms they're familiar with.
No it isn't solving 100% the same problem, but I'm not sure that is likely to happen in one shot. This would create the interface first. Let them work out the bugs between what can and can't be shared, and later they could try to unify the packages themselves (parameterize what can be shared, etc).
Or maybe I just don't understand all the problems they're solving here. As it stands they're duplicating the native package management work AND making a new interface, right?