Raspberry Pi ...
ARM is on my list of things to do, but I expect that to be 1 to 2 years away.
I did do a proof of concept and the normal CPU core I have will run on ARM, but it is way too slow. It was probably in the range of a 386 computer.
I have a x64 CPU core that is pretty fast, maybe 25% of the host system. It works on Windows and I'm hoping to have it working on Linux soon. Perhaps that would work on small x64 system, like LattePanda.