There looks to be an installer image on files.devuan.org for bbb/armhf boards (not sure if they work, can't verify due to headless setup), but no images that can be flashed directly to sdcard only for headless setups.

vmdebootstrap may be used to build but has a couple of issues with the example that comes with it

from /usr/share/vmdebootstrap/examples/beagleboneblack.sh the changes I had to make were:

--customize "/usr/share/vmdebootstrap/examples/beagleboneblack-customise.sh" \\

--bootsize 75m --boottype vfat \\ (50mb was not enough to complete the build)

--mirror http://packages.devuan.org/merged \\

--package u-boot-omap \\ (since using every u-boot package is not necessary)

--distribution jessie \\

--root-password=rootpw (passwordless login seemed to fail)

--user=username/password

--image=devuan-bbb.img