About the only thing available now which can handle these huge amounts of storage is the USB stick. It needs a very specific extension to the SD card interface to get past 32GB. An external SSD could use something such as Ethernet to connect, and I have a small box-thing which can connect an SD card via wifi or Ethernet.
I can remember USB expansion cards which used a PCI slot, had the usual row of sockets accessible from the back of the computer, and had a single purely internal USB socket. It may have been meant for one of those connector boxes that occuply the space used by a floppy drive, though these now use a different internal physical connector. not compatible with an unadorned USB stick,
If I had a couple of 64GB USB sticks in a RAID configuration, already possible, that aren't dangling in open air, that might be interesting. Move that approach to the TB scale. But I have seen similar multi-card RAID using SDHC, and I wonder if they can get the reliability.