ECS has released ARM versions of its LIVA brand of mini-PCs. The Q1A and Q1A Plus have Rockchip SoCs, 2 GB of LPDDR3 RAM and measure just 74 x 74 x 34.6 mm. The two machines run Android 8.1 and Ubuntu 18.04 natively.
https://www.notebookcheck.net/ECS-LIVA-ARM-versions-of-mini-PCs-introduced-that-run-Android-and-Ubuntu-natively.515137.0.html