One suggestion already posted here somewhere is to store a copy of all FDR/CVR data in a small, lightweight and fairly "unprotected" memory compartment in the vertical stabilizer.
In recent impacts on water the stabilizer floated and was quickly found in a pretty much intact condition (e.g. AF 447, AA 587, NZ A320)
At different accidents the established fire and crash resistant FDR/CVR would be available.