I made a few modifications to the nice Adafruit design:

• I thought the camera cable hanging out was an unsightly blemish on an otherwise nice design, so I made the back cover a bit bigger to accommodate it.   You have to fold the cable, but it fits.  I didn't bother to make a better clip for the back, so it may need a bit of tape/glue.  Mine seems to hold together OK, however.
• I made the PCB board mount a bit sturdier.  With the skeletal mount provided by Adafruit, handling the camera by the actual case put a huge amount of stress on the 1-2 mm of plastic holding it together; it was flexing and close to breaking.  So I made it better.
• I added 12mm standoff washers, in case (like me) you don't have the standoff bolts and just want to put it together with normal bolts from the nearest hardware store.

I included the fusion 360 file.  It complains about some buggy features in the timeline but it seems to work regardless.

Please feel free to comment if you have any feedback/questions.