Uma solução alternativa do usuário EvanDeaubl: link
I'm currently storing git repos inside of my annex by using a separated git dir, so that git doesn't detect the nested repository and balk at adding it. Doing a git clone or git init with a --separate-git-dir= argument puts what would normally be in .git in that directory, and creates a simple .git file in its place which references the separated git dir.
When I'm not using the repo, I move the .git file out of the directory, and everything looks like regular files to git-annex. When I want to use it, I move it back in place, and any git operations inside the repo directory use the inner git repo itself.
Another option I used for a while was to store bare repos in the annex, and doing checkouts from those repos.
Não é exatamente uma solução, mas pode ser uma solução viável.