Portable, Wireless File Server for the Car?

Kerhop wonders: "I'm looking to implement an off-site file storage location but want it to be convenient for me to access with the right security credentials by placing a portable file server in my car that has at 802.11b ability and is battery powered (but also recharged via cigarette lighter adapter). I've found the Sony FSV-PGX1. I am curious, though -- what solutions have others found?"