For a niche category of products targeted toward serious photographers, there sure are a number of companies that have come up with battery-powered hard drives that can suck photos off of your memory card for reloading or backup in the field. Epson’s P-series with their gorgeous Photo Fine displays are the best known, but other companies include Sanho, Jobo, (not to be confused with GorillaPod maker Joby), Wolverine, Digital Foci, and MemoryKick.
One neat feature of the relatively compact, colorful and stylish MemoryKick MediaCenter device is that it can transfer files on the fly from one form of removable media to another (as well as USB host mode) so one could, for example, grab a few photos off of an SD card and put it on a friend’s USB flash drive. At over $200 for a lower-capacity model, they are far too expensive for that simple task, but I’m always happy to see possible solutions for in-the-field sharing of digital photos, long a pet peeve of mine.