Wiring (at this moment) is quite simple:

I added a USB breakout which I use as input. It is connected to the raspberry pi and to the VFD display. The display supposedly takes in a lot of power, so I'm using a beefy usb charger, without problems. There's is no battery yet, but the space for it is reserved at the left, just haven't got the time to think about that yet and buy something that suits the project.

The VFD display is hooked up to the raspberry pi via the SPI interface. Meanwhile, the keyboard is powered by the 3.3 source on the raspberry pi. 

Besides the battery, I also want to add a few LEDs to highlight some details and glow in the same color as the display. Furthermore, two of the usb ports are reserved for the deck and I have a little USB hub to put inside the case to expand communications.

Also, don't forget my original plan is to use this for logical IO and serial, so there's some space and cutouts on the back for that that too.