A more likely candidate would be IX systems, makers of TrueNAS. They already have hardware they sell with TrueNAS, so building something for HexOS might be as simple as changing the software image that is installed, possibly with some branding/aesthetic updates from TrueNAS to HexOS.
Most of IX's offerings are 19" rack-mount chassis, but they do also have a couple smaller units: https://www.truenas.com/truenas-mini/