The nix store can do hard linking for the hashsum files. The nix store is read-only so you don't get modifications in general - does not really matter for boot disks, but in general.
Unlike in FHS distros where you get some of the separation for free with usr/lib vs usr/share, most nix packages don't have separate store paths for binary vs non-binary files. At most you'll get the headers and build scripts split off in a separate dev path.
Those ternary blobs tend to be cross-platform, I hear.