My main dislike of black panel designs: I can’t see the knobs as well.
-- Kaleidic
It's true. As a pianist, I actually prefer a traditional white (ivory) keyboard with black (ebony) keys than the other way round. It's more 'readable'.
To complete the original topic, black or brown wooden piano cases were often multicoloured in the past on... harpsichords. And they were magnificently painted.
However, with the psychedelic movement, some pianos were repainted in the 60s. One of the most famous is Lennon's (painted by Dutch design collective artists The Fool).
Today, these different trends can be found in synthesizers and modules.
'On ne devrait jamais quitter Montauban' (Fernand Naudin).
https://soundcloud.com/petrus-major/tracks