Yep, was about to suggest the same thing. The cable included with those card readers fits your specs exactly. It's not required for the card reader either. It is meant to be used to make the card reader portable, but the card reader normally has a regular USB cable hooked up to it so the short little cable is entirely superfluous.

The other option would be one of those Brando mini-usb adapter keychains. Can't get much smaller and more pocketable than that--and the price is right:

http://usb.brando.com.hk/prod_detail...015&cat_id=042