Dell sells these. The link is to a 32 MB version, lower capacities are also available. I got an 8 MB version directly from
IBM, which I really like, but now I'd go for a higher capacity version even if it cost a little more. PC Mag and/or PC World have had articles on these recently, I think, and could tell you about some similar options. I don't know if any go as high as 70 MB right now, but I remember reading that 512MB capacity in the next year was a possibility.
They are USB, so Win NT usage is out, and on Win98 you need to install drivers (but later OS's have the drivers already in them). The drivers easily fit on a floppy (around 64K) and can also be downloaded I think.
The Keys are quite handy for "sneakernet" sorts of things -- quick to use and they hold more than a floppy.
My biggest use for them was when I had a laptop with no CDROM. I put the drivers for an Iomega zip on them, installed the drivers on the laptop, and then attached the zip.
Anyway, a neat little gizmo that can come in handy.