My Samsung S3 phone accepts an OTG USB cable that you can put a memory card reader into, and the phone has a slot for an expansion SD card up to 64GB. There are obviously tablets that do the same.
I even found that I can plug a USB floppy disk drive in and it works.
A few months back I found a battery powered external hard disk that had memory card slots in it. Just plug the camera card in, and it automatically backs it up. The hard disk can be attached to a PC as an external disk at any time to retrieve the photos, or just used as an external disk for other backup. Let me know if you are interested and i'll dig up the info on it.