Needed a low profile, no-frills case for a project I was working on and found adamwdraper's nice deisgn. I only had M2 or M3 hardware and his called for M2.5 so simply remixed to use the M2x16 hardware I had on hand. I also added the extra hole for the PoE header.
Note this also works in "convertible" mode by mounting only to the bottom piece with M2x8 hardware.
This was completely modelled from scratch using the dimensions provided by the Raspberry Pi organization but my inspiration and overall design was based off of adamwdraper's thing which gave me the inspiration.