I've spent a week making git-annex be able to store files in a remote on a server using git-lfs.
That included writing a haskell implementation of the git-lfs protocol. That could be split out of git-annex into a library if someone wants to use it for something else.
Now git-lfs is now just another special remote as far as git-annex is concerned. Albeit one that it can't drop data from, because the git-lfs protocol does not have a way to delete an object.
Once nice thing about git-annex's support for git-lfs is it can be used along with git-remote-gcrypt, and the result is a remote where both the annexed files and the git repo contents are both encrypted.
See storing data in git-lfs for details.