[lunch]

I would like to see NASs allow me to basically allocate a percentage of my capacity to various peers to store encrypted-at-rest duplicates of their data

This is something I've been thinking about, too. We have so many Internet-connected devices with increasingly cheap storage-- Some universal protocol for distributing data across this network would be really cool. (I understand this could sound like blockchain. I have no horse in that race.)

[smacktoward]

I would worry about the liability implications of such an approach. If one of those peers is storing (say) child porn, and some of that porn ends up on my hardware via automatic duplication, does that implicate me legally in their crime? If it does, does it matter whether it's on my hardware with or without my knowledge? If the police identify my hardware as part of that peer's storage network, is that hardware at risk of being searched and/or seized? That sort of thing.