The Radxa Orion O6 is the first midrange Arm ITX motherboard... but I can't recommend it. Yet.
See why here: https://www.youtube.com/watch?v=OMnCqmM-WKo
@geerlingguy Luckily we have new Snapdragon CPUs soon, nVidias new ARM stuff, and who knows.... maybe Raspberry Pi might make something.... We can only wait and see.