Ok, here’s the sliding part of the room node mount:
Totally hacky for now, the reinforcement bits are all glued in and cut to shape.
What totally surprised me, is that the JeeNode itself barely fits, even though there seems to be so much empty space in there. The tricky bit is that it can’t stick out on either side – in the end I could only make it fit by turning it a little, and moving the battery pack out of the way to make room for that orientation:
This thing is larger than I expected it to be – the big triangle against the ceiling is 14 cm on both sides and ≈ 20 cm on the long diagonal side.
Last step will to to figure out a way to mount this concoction. Oh, and then redo it all from scratch to create a decent printable DIY template.