They're not PCMCIA, which is why you're not finding any. (In fact, any USB 2 cards labeled as "PCMCIA" are mislabeled, since PCMCIA isn't fast enough for USB 2, which needs CardBus speeds.) Search for "CardBus" cards and you should have more success. Also, it's "USB 2.0", not "2.0 USB". I know it's a tiny difference, but search engines (especially those on vendor sites) can be VERY picky about things like that.
tooki