I originally designed that layout to work with kmiller8's 40% PCB design. He included it in his layout options. That's about as small as I can get it. I wanted it to stay rectangular, and use commonly available keycap sizes. And I like a full size spacebar on my keyboards. I will probably eliminate all redundant keys, like the 2x Ctrl and Alt, in favor of others.
I really like that KB Layout Editor. Very slick and helpful!
The plates are only ~$25/ea from The_Beast. His laser guy does an awesome job cutting these. I've always liked the idea of using the plate as a "case," also. Like in the original Dox design. The Dox is what inspired my call to action on the GH60, which in turn helped motivate komar to design the PCB. I have a couple more design ideas I'm going to be prototyping like this. It will let you know if your design is usable, without the expense of having a custom PCB made.