Your best bet is actually some "old tech" that is now CHEAP tech if you can find it.
back in the day before multi gig memory cards we have a problem with high resolution camera's - filling the damned cards and running out of space.
so we had these gadgets it was a portable external 2.5" laptop hard disc but the enclosure had a screen and memory card slots.
you pop your sd card into the slot hit GO and it dumps the sd card to the HARD DISK.
the nice ones had a small LCD screen so you could see the pictures you downloaded AND (important) verify a good transfer
the older Creative color screen hard disk players ALSO did this.
I forgot what they "CALL" these things I know they are on ebay but lack the memory of what search terms to use to bring them up
I did find an example of what I mean on buy.com for $250
Buy.com - DIGITAL FOCI PICTURE PORTER 35 250GB
you just plug in your memory card and download its contents to the hard disk. now you can reuse the memory card.