I was able to build, boot and login to an Ubuntu Core 18 based image just now (using my own store). I posted more about it here for those interested:
https://discourse.freetocompute.org/t/built-ubuntu-core-18-image-logged-in/41
This has a lot of gears working together to make this happen but I liken it to being on step 2 of 1000 that’s toward a release that still would be the most minimal possible.
But, nonetheless at least mildly interesting! Maybe?