I'd also like to ask about single-board computers that can run some version of Windows. I'm quite a fan of the Raspberry Pi, but there are times when I'd like to use software that only supports Windows XP or newer, and WINE doesn't cut it (e.g. iTunes with iPhone drivers, Age of Empires 2, PowerPoint).
I believe the Raspberry Pi 2 and later all support "Windows 10 IoT" now [0][1], but if memory serves IoT has a lot of limitations.
It might be simpler to have a minimal distro that boots directly into something like QEMU, that should let you run Windows XP on the Pi.
[0] https://www.raspberrypi.org/blog/windows-10-for-iot/
[1] https://docs.microsoft.com/en-us/windows/iot-core/tutorials/...
QEMU has easy GPU passthrough, so that shouldn't be a hassle. And whilst the USB options are slightly more intimidating, you can passthrough that as well.