What is the state of container libraries?  I am looking for a library which provides:

* unordered containers (for "operational" type safety, I don't want to impose orders on things that don't have them -- unordered containers does this)

* can handled nested containers (containers does that)

* can be serialized easily, or better yet, has Generic instances

Does such a library exist?  What are you using for Set and Map needs?

I have been fond of unordered-containers for a while, but found difficulty in creating HashSets of, for example, HashMaps, since there are no Hashable instances for their polymorphic types.  I even dug into the code, looking at the possibility of submitting a patch, but gave up when I ran into funky #-suffixed values, which stymied my initial attempt.