There is no board with a PCB that I know of in that layout.
Having a custom PCB made can often cost more than having a custom plate made, so I'd go with a plate designed in swill's tool and hand wiring to a Teensy 2.0.
Cheapest and most flexible option, IMO. Also, feels better than PCB mount.
I don't think youll find an existing 75% case that it will fit in, either, as all the ones I know of have one less column (Noppoo Choc mini, KBT Race and Race 2, Keycool 84, etc).