I've been secretly and passively working on an XMPP Lisp library. I was having trouble with SASL, but I got that going after properly configuring my server (the order of
auth_methods in ejabberd matters!). Since I can actually login, I've been seeing if I can login to my various accounts. So far I haven't had much trouble until I tried to login to Google's Talk server.
For whatever reason, Google decided to invent their own SASL method: X-GOOGLE-TOKEN. This is also the only SASL method they support too!
It might be to brash to damn them just yet. I haven't tried to get TLS working, so the more common methods could still be lurking behind that wall. Consider this a warning to other client developers, you may need to support TLS to play on the Google server.
More updates to follow...