Apologies for the absence but I've picked back up on the project and been quietly working away at design tweaks to aim for the best possible experience in both manufacturing and with building in the case.
The layout and overall style of the case has remain unchanged, but now it's been updated so that it is possible to have all exterior panels laser-cut, not just the sides. This would help give the case a more premium feel as well as look more attractive in your setup.
Here's a refined design with Flex-ATX support. The power button goes in the large round hole in the back.