Hello.
Exist a SATA to SD-Slot Adapter?
If not, this is "your" chance for a Crowdfunding project...
Using a big cheap HDD at a camcorder etc..
For example, with case, battery and 1/4" thread (for mounting on or under the camcorder/camera).
That would be a big advantage.
12.5MB/s, ~750MB/min...