I have a plan for this month. While waiting for telehash, I am going to build git-remote-daemon, which is the infrastructure git-annex will need, to use telehash. Since it's generalized to support other protocols, I'll be able to start using it before telehash is ready.
In fact, I plan to first make it work with ssh:// remotes, where it will talk with git-annex-shell on the remote server. This will let the assistant immediately know when the server has received a commit, and that will simplify using the assistant with a ssh server -- no more need for XMPP in this case! It should also work with git-remote-gcrypt encrypted repositories, so also covers the case of an untrusted ssh server where everything is end-to-end encrypted.
Building the git-annex-shell part of this should be pretty easy, and building enough of the git-remote-daemon design to support it also not hard.