The Desert Wind operated with a mix of Superliners, Hi Levels, Amfleets and Heritage for a while in the very early 1980s. They used a Hi Level transition coach (that had not yet been converted to have dorm rooms on the transition end) to do it. I rode it in early 1981 and it was a Superliner coach, a Hi Level transition coach, an AmCafe and a Heritage 10-6. It could be a really oddball train in its first few years. Unfortunately, I didn't really appreciate it at the time and I seem to recall being vaguely pissed off at its weirdness.
That predated the Superliner II trandorms by more than a decade, though.
I do not think transdorms were ever used that way in regular revenue service. The only thing that comes to mind was an executive "grand tour" a few years ago, where they used a transdorm running "backwards" so they could run the Beech Grove biz car, which is pretty much a blinged out Amfleet, to hook onto Superliner trains. I think it was shortly before COVID and may have been during Anderson's Reign of Ignorance.