Aaargh!!! I feel for you, because I've been living with the exact same problems for going on three years since the dropouts began and at least a year since iTunes/AirTunes began losing connection with my AirPort Express, but
still playing. You can read about my past hair-tearing
here and
here, but not about my new, perhaps related issue of iTunes/AirTunes losing connection with my AirPort Express and
stopping playing which, shying away from further frustration, I haven't posted. Aaargh!!!
I'm both truly sorry and aggravatingly disappointed that I can't be any more helpful.
Edit: It's really difficult to say with confidence, because the nature of my issues is that they come and go randomly, but Apple's having changed my deuced Mac(hina)'s fan may have actually resolved my initial non-connectivity issue.