Intel Compute Stick STK1AW32SC
Specifications at http://ark.intel.com/products/91065/Intel-Compute-Stick-STK1AW32SC
Drivers & Software at https://downloadcenter.intel.com/search?keyword=STK1AW32SC
BIOS has support for 32- and 64-bit UEFI booting, secure boot can be disabled, make sure the latest BIOS is installed.
Arch Linux installs and runs fine on an external USB3 hard drive.