Nothing that I'm aware of...I don't watch a lot of youtube. The biu bong is found in Chum Kiu after the first kick where you are stepping with bong-wu. It is also found throughout the wooden dummy form.
Okay, that section is called paau-bong (throwing bong), but it is not different from the other sections. There is only one bong-sao concept as an elbow rotation. In the 2nd CK section it is coupled with wu-sau to form kwan-sau, which is the bong and punch together, although not completed. It is trained this way for simultaneity of the step, elbow, and punch to improve speed, timing, and full body power.