Not sure if this counts but at the end of disc 3 of BTAS Vol 2, there's a quick audio clip of Shirley Walker saying, "I'm only sorry we have to get back to work after all this fun". I suppose that should count given that the nomination speech from disc 4 has already been noted in this thread.
There are also two easter eggs on STAS Vol 1: at the end of disc 2, there is a speech from Shirley Walker in which she talks to the orchestra about Bruce Timm, and at the end of disc 3, there is a very quick audio clip of someone saying, "Direct from the city of Metropolis... 104, take 32" (or something like that).
Thanks for the update! :-) I would request LLL team to include more of these surprises in their releases and maybe sneak up an alternate cue when possible. That would be ultra cool.
I discovered the "Superman: The Animated Series" egg mentioned earlier with Walker announcing Timm to the players.
It's disturbing to think after the quick success of B: TAS, that Walker would recant that Warner Bros. actually asked that if after 30 or so episode scores to S: TAS, if they could just track the rest.
Ordinary People and Save The Tiger- Marvin Hamlisch
Track 46- "After Romantic" (From "The Tiger".) Second half of this track has some recording sessions dialog for "Ordinary People", and it goes into a short cue called "Gappy Happy". Or something like that, it was hard to hear what was said.
Got B:TAS Vol 4 for Christmas, and there is an easter egg after the final track. I can't recall what it is - more studio chatter and maybe some playing. Sorry I'm being vague, Internet thread! I just remembered to post this a week after I finally listened to it.
I found a hidden track on LLL's The Passion of the Christ by John Debney at the end of "Resurrection Choir", last track on Disc 2. It sounds like the main theme, and an emotional vocalist, but I can't tell if it was an early attempt at the theme, a concert performance, or what.
