Like Wobbly John says, it's been done before, probably many times.
This is one I took some photos of at a BHPC meet back in the 90s, although I'm not sure exactly when. It could be the chap who John is talking about, I don't remember his name.
On that bike, one of the limitations was the space between the rear wheel and the riders nadgers!
One novel feature of the video, that I haven't seen before, are the mirror headset arrangements that the riders are wearing, and which allow them to stare at the ground, and still see where they're going.