Does anyone know of an External HD that can be used with the iPod Touch 4g? I am talking about an external drive that you can carry on the road with the iPod touch to store music, documents, etc.... I would like to use the iPod Touch as a PDA so I would like to carry an additional drive to connect to the Touch and use the drive as extra storage. I know HyperMac makes a similar external HD that can be used with the iPad to store additional files. I haven't seen anythng made for the Touch yet. Any suggestions?