there are lotsa OS's and versions or derivatives of them, so my 1st question to your question would be, what do you need to use tin Devuan that is not available in one of the (now many) arm6 hf OS images.
If you want speed and size, then I recommend PipaOS (Wheezy+Xgui or 512/256). go to the download directory, as it contains some newer images and a kernel folder
alternatively there is a couple of ways to build your own arm6 hf Devuan, and that is to point an APT-source to Devuan's src/source repo, and (using a Debian based OS) build the newer Jessie versions of any binaries from source through APT. That should work for any Wheezy based image.
If you dont need gui then there are quite a number that would be a good starting point.
I do realize tho that this is time consuming, eg. a full gcc 6.1 build takes something like 12 hours on a Pi. If however (like me) you have a spare Pi or 2, and a bit of time to do some research (chroot, sysroot, etc), you can let one chug away, possibly with someone elses (automated) OS distribution build scripts.
Basically I would say that the main reason why there is no Devuan armv6 hf is because noone who "needs it" has found a simple way, ie there are (maybe) lots who want it but aren't willing to give it a crack. It is not rocket science, but it will require some effort (ie time).
Another alternative is the approach I'm about to take: start with picore 8.0 or PipaOS (Xgui wheezy 3.5/ 5.0 guarana jessie) and build anything else from source, or a source repo (like Devuan). Storing the packages and build order and new dependencies for later user, or so someone can publicly host them.
I have a couple of non-ARM OS's that require manual installation to setup, but I want to be able to share the results (for various reasons) so I will use something like MegaNZ which allows 50Gb file access per free-user via an ssh type client. I chose MegaNz because they have well documented API, client sources, and some examples, enough code to build a FuseFS module, and enough flexibility to allow "on-demand-pull" so you would not have to install the whole OS at one time (like you do with an .img)
But thats me, and I have specific requirements too: command line autologin hotel wifi, cross-compilers, full SDL 1.2, customizable boot splash, non-standard R/W filesystems, etc
Its also very easy to build linux style OS yourself, but you really have to do a lot of reading to understand what makes a bare minimum OS usable, from console & ssh, or just as a binary runner (like Win10 IoT Pi)
Hope this gives someone some ideas, and hopefully it wont take me too long to make something usable available (I will try to remember arm6 hf as I have 2x Pi B doing nothing for 6 months now)