Maybe we can add MGM's 1946(ish) "Holiday in Mexico." Turner has a great coming attraction for it including what appears to be the ending with orchestra, chorus and Jane Powell.
One of my favorite MGM musicals is "Deep In My Heart" which was issued as part of a Composers box set on laser disc. The image was widescreen and the musical stereo elements were used. I'd love to see an anamorphic DVD with the stereo preserved. And, I'd love to see a tribute to Jane Powell...