Nothing worse than building a custom PC and losing case parts. The worst thing you can lose is the drive caddies/trays/rails. I get you can't support everything forever but why not make it easier to find replacement parts? This is why for the longest time I have hated custom builds. Lose any proprietary part and you are hosed.
...
https://www.youtube.com/watch?v=0dGd2QWXUpw