So I posted this some time ago.
Now that I have a glowforge, I can make it myself. I generated the finger jointed box here…
Then went to Illustrator to remove the top row of fingers for the sides and al of them for the top. Then started adjusting the top and added the raster shapes for the grooves.
I used medium maple plywood and adjusted the engrave to make two passes to get the correct depth.
I had to run a piece of scrap through each groove a few times and add a bit of soap to the edge and works like a charm.