If you can find a data recovery service, they "may" be able to break open the tablet and access the eMMc chip itself (that is the storage drive on the tablet). It is soldered in but some services can desolder those and attach clips to the data points on the chip and retrieve the information from it.
It takes equipment and people who know what they are doing. Same process in recovering information from damaged black boxes from airplane crashes.
If you can check around some electronic repair shops, they may either do it themselves or know somewhere where you can have it done.
Probably won't be cheap to do!
Flash and SSD storage to include micro-SD cards are very difficult to get information off if the computer/camera/phone that it was in dies.
If anything, you could probably contact those at http://www.ifixit.com and they may know who could do it. The tablet would be destroyed but may be able to get the information off of it.