I agree with most points, but I'm not proposing creating integrations with other DVCS, en par with the current Git integration.
My proposal was a little more crude: get the channel code from a tarball. In this model there are no authentications with fingerprint or signed commits, neither "guix pull" would know much about the before/after state of a channel besides comparing the checksum of the whole tarball. This lower level abstraction is much less sofisticated, and would probably mean refetching and rebuilding from tarball-backed channels than Git channels. But this also means that the requirement is lower, and much more universal: a tarball file served over HTTP, compared to a specific Git HTTP protocol.
