CernVM-FileSystem is a POSIX, read-only, FUSE, filesystem for software distribution. It is mostly used in private datacenters (mostly HPC) to distribute software to thousands upon thousands of computing nodes.
I create a public CVMFS repository one to easily distribute common software. Nix and nixpkgs were fundamental in allowing to bootstrap the software stack.
I believe that building software with Nix and distribute it with CVMFS could really be a major step forward for what concerns the usability of complex software stacks.
More information about the project on the github repo, RedBeardLab/packages.redbeardlab.com