So you printed the multiboard and need a round container?
Got cottonpads to clean your printbed? A can of compressed air? Measure, customize and print it! Use snaps to attach it to the board.
There is also a cubical version: https://www.thingiverse.com/thing:6527050
Like the design? Buy me a coffee ;)
UPDATE: added the option to make a hole in the bottom, some tools will better fit this way.