After digging quite a bit I found the following:
git and/or github is not required to use Chef. If another version source control system is preferred over git (such as Subversion, Mercurial, or Bazaar) that is just fine.
and
Download the chef-repo as a tar.gz file and place it into local version source control
and
(Optional) After the chef-repo is cloned, the history of that repository can be wiped out by removing the ”.git” directory, which allows the initialization of a new repository or to move the chef-repo into another version source control system, such as Subversion, Mercurial, or Bazaar.
..from here.
There are no details however, of any limitations this presents, so I would assume there are none.