I have a couple of Hyperdrives, both designed for my iPad I when I traveled exclusive of a computer. One had an SSD; the other a conventional drive. Worked great! Used them to back-up my SD and CF cards. However, that generation maxed out with 32gb cards and is no longer available, replaced with better.
At one time, you could just buy the bare Hyperdrives and use your own drives which I did since I could get larger drives much more reasonable in cost than the canned drives and it would only take five minutes in install the drives.
I still travel with one of the Hyperdrives at a minimum, but since my needs now include video capture and editing and many times need to turn-and-burn on the road, I've had to up the anti and now travel with a MBP 13 with SSD and a couple of external drives so I can fully edit in the field, though I'd just as soon rest and socialize like during the days of film! :-p. Maybe one day again!
I know there are other solutions out there and that the iPads are finally available with lots more speed and storage along with full Photoshop capabilities, so who knows what the future holds. But if you need something today, get it and worry about the vaporware as we once called it when it hits the market.