I created a Windows To Go flash drive using 64-bit Windows 8.1. It boots and works perfectly except that I cannot activate it with the license key I got when I paid for Windows 8 last summer (I bought the digital download, ordered the optional disc, and carefully recorded the license key Microsoft e-mailed me).
I noticed that the "build" of the Windows To Go flash drive states "Windows 8 PRO," not Windows 8 or 8.1. Did I screw up and not install the right version of Windows to the drive? Is Windows To Go only for the PRO version of Windows 8 and not the regular version? I only worked on this as an experiment to see if I could boot Windows 8 on our work PC's (which are sadly still running XP), and I am so close! Where did I go wrong?