We discussed this issue some 25 years ago at the IFALPA Accident Analysis Conferences I use to partake in. Sadly and even more so today, the press would 'kill' for such footage and with their wonderful reputation for accurate reporting (Cynical old me), it would be the last thing any of us in the profession would like to see. Especially the relatives if the accident was a fatal one. As a tool for accident investigation though it would possibly be very useful. An example I believe in the B777 accident at KSFO, it couldn't be clearly established who was handling the thrust levers and so a camera would have quickly resolved. this.