Searching wex for "hard drive sd card" produced one result - Western Digital Passport option that may be okay?
Can't find any others... ok, a bit more searching found a "NextoDI ND2901" which has more features including previewing images and (probably) replaceable 9.5mm 2.5" SATA.
Fill an SD card? :?
You either have too many megapixels and/or too few megabytes.