It's interesting that you mention Macbeth. I have a recollection of seeing a witches' ballet from this opera, in a clip shown on Classical Arts Showcase. I gather that the long ballet was added for a performance in Paris, where such things were expected and required.
I just looked it up in Philip Gossett's
Divas and Scholars. He describes the following, from a performance in Parma. The ballet occurs during the witches' second encounter with Macbeth (act 3).
QUOTE
The Parma production in autumn 2001 of the 1865 Macbeth was anything but traditional. The witches in the third act were clothed all in black, in ankle-length dresses with ruffs on the sleeves and around the hem. Each of them carried a black purse. During the chorus in which "aerial spirits" are supposed to descend in order to bolster Macbeth's flagging courage, the moved those purses back and forth rhythmically in a gesture that was at once mesmerizing and absurd, drawing guffaws and obscene comments from the loggione.
But those comments were nothing compared to the ruckus that accompanied the ballet, where these Mary-Poppins-like creatures gathered around what appeared to be a big soup kettle at the beginning of the scene. After their initial chorus they sat down on neat rows of chairs, and soon began to watch a powerfully disturbing movie, which employed scenes from the second World War, bombs being dropped from low-flying aircraft, flame-throwers and tanks, goose-stepping troops, desperate lines of refugees. All of this was timed with Verdi's ballet score in a way that seemed almost choreographed, rhythms of the music and rhythms of the visual images in uncanny synchronization.
Among the outraged comments from the audience: "If we wanted a movie, we'd have gone to the movies."
The version I saw in video, which I believe was from another Italian opera house, was more conventional: lots of writhing, arm waving, etc. Far from classical, but definitely a "ballet" of a sort.

I enjoyed it.
I can't imagine where the ballet was in Trovatore -- possibly the gypsy camp scene (as in Don Q)?