Have you thought about including mounting points and a rear plate for HDPlex support in lieu of the FlexATX PSU for people who want to go low power with external bricks? That would definitely help with noise.
That can be done, but this feature would probably end up being implemented without being tested with a physical unit.
Currently, I think that the mounting holes would need to be in a rectangular 122.12 x 43.29 mm pattern, likely for M3 screws, a 12.5 mm wide circular cutout is required for the DC jack, and overall board dimensions are 52 x 160 mm. Not sure how much space cables need.