Found this website with dimensions of inches few days ago.
I'm also planning to make my own scratch PC case (probably it will be aluminium or MDF material because I have full access to CNC machine) for mATX motherboard and full-size PS2/ATX PSU and 2 slots for 2,5" SSDs. Also I'm going to put new PC to this DIY case (already bought Saphirre Nitro+ RX 580 8GB for 160 bucks and waiting for good deal of Ryzen 2600).
If anyone has any ideas or suggestions for my DIY cass, feel free to write me.
The highest-tier scratch DIY case: https://rog.asus.com/forum/showthread.php?33109-Scratch-Build-Model-01-by-Brodholm
4 videos about making case with basic techniques (link to 1st video):
Also in 4th video price is mentioned.
DIY Perks is great channel of DIY videos as well as PC cases ones