iTunes 11.0.3 was released today. Mods to the Mini player seem to be the most obvious. Under the hood, AppleScript has some new Airplay access.
First, there's a new Airplay device class and AirPlay enabled and current AirPlay devices application properties which should make scripting Airplay operations pretty easy. I'll have some stuff later.
The track class gains a iTunes U property ("is this track an iTunes U episode?").
More as it develops.