In the late 1970's video performance with Makarova and Nagy, there is a pas de deux in Act IV with a beautiful piece of music whose main theme is set to a solo cello. I've yet to find any audio recording or another video in which this pas de deux/music is included. Can anyone shed light on this?

Melissa, I saw this production many times and should know this, but I don't -- I was hoping someone else would respond.

I don't remember your posting on the Welcome forum; forgive me if I missed it. But I don't think you have been officially welcomed, and so I'll do it now, albeit a bit belatedly. You've brought up quite a few interesting ideas and asked some good questions, and I hope you continue doing both!

I think the piece your are referring to was choreographed by Ashton for the RB (Carl Toms) production in the late 60s.

Since the Blair production was supposed to be after the Sergeyev production, which was after (some distance or other) the Petipa/Ivanov Swan Lake, I always assumed that pdd was Ivanov's.

I really do miss that Blair/Ivanov fourth act.

Do you mean the Drigo-orchestrated Tchaikovsky piano miniature, "Un peu de Chopin"? It definitely starts in the cellos, but not a solo, in my recollection.