Ok, I am going to come at this one from both sides.
1 With my instructor hat on, I would love to be able to review and critique my own performance in order to continually improve - well I am in the process of implementing TEM and LOSA in my day job. I also think this would be valuable for most students and would probably serve to reduce training time for those students unable to fly on a regular basis.
2 With my instructor hat on, I would be more than a little wary about the consequences of loose articles in the aircraft - I would want the installation of any article as significant as a normal sized camera to be installed and certified by an engineer, even if this does mean a minor mod.
3 With my day job hat on, I may just suggest in flight cameras as a means of moving forward. Provided flight video can be collated by an impartial 3rd party there is the possibility to glean a lot of data that would otherwise be swept under the carpet at the back of the cranium.
RIX