What you want is nearly possible: Intel's current generation of Compute Sticks (CS325 and CS525) are the size of a USB stick but have 2 cores, 4GB of RAM, and 6

What you want is nearly possible: Intel's current generation of Compute Sticks (CS325 and CS525) are the size of a USB stick but have 2 cores, 4GB of RAM, and 64 GB of disk space. Granted, you can't use it on the go but it is ultra portable.