Just wanted to share a project that I just finished up -- print a Raspberry Pi blade-style rack mount for a friend here on the forums... It was a fun project to create and experiment with and I think would be pretty functional if anyone is actually interested in creating one themselves. @DaveL can let us know how it works in practice when he gets to try it out.
The models can be found here. They provide the STL and Sketchup files, though I haven't opened the model files yet - just printed the STL as-is. The only issue I found is that the sleds are a tiny bit too loose for my liking, so you can see in the final picture where I added a small bead of filament w/ a 3d filament pen to make it a tad tighter.
I printed this in ABS though PETG would be another good choice; I avoided PLA due to the potential for elevated temperatures once installed in the rack. Sleds took ~1 hour each, the receivers ~4 hours. I don't remember on the end mounts but they were quick, probably around the sled time. Clean up was pretty minimal - I printed w/o supports so there was a little bit of cleanup on the overhangs to ensure a tight fit upon assembly, but this really was minimal. I am working on adding a multi-material upgrade to the printer and might have used supports with a water soluble layer between the support and model if I had it in place during printing. But the only "rough" spots from the overhang, really, are at the back of the receiver where the sled covers it anyway. Just OCD flaring up...
Final assembly and some in-progress shots below...