Given that digital data recorders are now dirt cheap and very robust, it might be easier to just add a dozen around the airframe.
They may be dirt cheap and robust but they still weigh a fair bit and take up physical space. Where in the airframe would you propose to site them, and how would you mount them? How would you get power and the various mic channels to them? And why would you go to all that cost and long-term weight penalty for a comparatively rare event? If you ask the accident investigators, they will tell you it would be better to have a second FDR than another 11 CVRs.