Having quite a few Pis I needed a case that could hold more than one in a single case. I am aware of two others that can be purchased, namely the Beagle Bone (and similar designs) and the BitScope blade. My Pi3's are running at 100% CPU load 24/7 so they need a case with active cooling.
I had previously done surgery on the official Pi case http://markjatboinc.blogspot.com.au/201 ... -case.html
but that left me with lots of individual Pi's scattered around my computer room (loft).
I ended up designing my own case and getting it 3D printed. I've already got some ideas for improvement in the next version. I've posted the rest of the images on my blog here