Does anyone have an idea about how much the necessary hardware and software to read every possible manufacturer´s black boxes would cost?
Well you seem fairly informed...
So how many manufacturers are actually supplying Airbus for the A320 FDR ? I might be wrong (I am an electronic engineer but not in that field) but I would be very surprised that there would be more than half a dozen. Would it be a Tupolev or some exotic airframe the story would be obviously different, but the A320 ?!
Why would the French board invest in something which will most likely be needed once in, say, 20 years when they know the manufacturer has the equipment in place and also people who have been trained to use it?
Given the number of A320 delivered I'm afraid that they will need to read FDRs much more than once every 20 year (not necessarily crashes, there are other occurrences when the data needs to be accessed). And there is definitely no guarantee that the manufacturer would be around... Sorry but IMHO the BEA is definitely in the business of making sure they can readily recover those information. Deferring to the OEM should be exceptional...
Anyway we should hear more factual information shortly.