You’re right, there are darker bred brown ones. But I was referring to the ones most seen in the wild and early breeding. Today there is a range of rare colors of orange and even to bright yellow. Red is still my fave.
Are they common in the wild? The only in-situ photos I have seen are of Catasetums and even then, mostly without flowers.
By the way, maybe because of the breeding trend toward the dark brown flowers, the chocolate (any shade of brown, reddish brown and all the way to dark chocolate brown) seems to be most commonly seen nowadays.
SVO's old catalogue included yellow cooperi. I have seen this olive greenish yellow one in its glorious presentation at Brooklyn years ago. What a sight!!! That was when I started to buy Cycnoches. The flower display, the flower shape, and the fragrance!!