

personally I like Arch first and foremost because I can (and do) have a local repo by rsyncing a rotation of mirrors couple of times a week.
Are these mirrors for prebuilt packages? If not, you should be able to pull from other channels, create your own channel and include all your packages while building them locally.
You have to setup a Nix service and do some symlink-ing
https://guix.gnu.org/manual/en/html_node/Miscellaneous-Services.html