After three weeks of little coding but much reading, a reward:
This shows the Chat activity talking to Empathy through link-local xmpp. This was already possible, but the difference now is that Chat is a normal telepathy client, and it has been activated by dbus as would be any other telepathy-enable application in GNOME, Meego or whatever.
The current code is very sketchy, but we are starting to get a good sense of the next challenges. If you are interested in knowing why this is important, see my previous post.
Progress can be followed in this page.