I guess I'm not following what's so special about "named data." Ultimately it's a mapping from a user-readable handle to a machine-readable handle. And no, such a mapping does not have to look like a filesystem at all. We don't necessarily even want a concept of directories as such, for example.
I'll grant that removable media presents a challenge. But with The Cloud(TM) these days, do we even need it? I'm talking about certain common use cases. Certainly we need it for lots of things but I don't think everyone in the world needs it.
Even so, I wonder if page migration could be adapted to support removable storage. Page out on one system, page back in on another.
Just thinking blue sky here, I'm not an expert on any of this.