I am amazed that this issue is apparently of such little interest to the aviation community.?
Have I missed the point that the opportunity to rapidly analyse the circumstances of all aircraft accidents/incidents is vital to improve on even the present level of safety or are we content with the existing situation?
You have (in my humble opinion) missed the point of why we have black boxes.
What you are advocating is something that will have little value to aviation safety. It would merely be a device to satisfy "human curiosity". A crash investigation is a complex process, where the black box is just ONE clue as to what went wrong.
Most black boxes (and crashed airliners) are found within hours of a crash. The wreckage will provide as many valuable clues, and in some cases the black box very little! (Check out the cases of 737 rudder hardover as an example of that:
Boeing 737 rudder issues - Wikipedia, the free encyclopedia ).
For the cases where a complete airliner has gone missing, the probability of learning anything useful, that will enhance safety is quite low anyhow.
Take the example of MH370, if there was a huge safety risk with the 777, most likely the wreckage would have been found around the area where the aircraft disappeared from radar. And not 4-5 hours in the opposite direction as there are indications of. Hence, whatever went down there, is probably a one-of case, that will bring us nothing to learn, if ever discovered. As a pilot, I really don't care why that aircraft disappeared (even if it was a type I was flying). As a human being, I am as curious as anyone.
Take AF447. Nothing in particular was learned from that either. It was know before hand that the pitot tubes of a certain manufacturer occasionally froze over. It is/was a know fact that manual flying skills are eroding. As far as I recall, even before the boxes were recovered, the pitot probes in question were being replaced. Recovering the boxes of AF447 provided merely an "aha!, that was why it went down".
So in terms of improving safety, the money on enhancements of black boxes that you suggests could be much better spent. In the end the airlines are going to pay for it. So, if imposing any extra costs on the (already hard pressed) airlines, the money would be better spent giving all pilot an extra day in the simulator
pr. year as an example - or a number of other things.