Check this out, Seagate's D.A.V.E. (digital audio-video experience), is a hard drive with a tiny 3.5 x 4.7 x .47-inch form factor into which you can cram 20GB.But its not just a ordinary hard-drive, you can share what ever you have in the hard drive using its onboard Bluetooth and WiFi connectivity. It's tiny, it will cost you a tiny $200 and tiny enough to snug into that shirt pocket.

Welcome to Seagate's "D.A.V.E.": wireless portable storage [Scobleizer]