7875 + 5.9 + E85 + Megasquirt

I'm very interested in seeing that. I do allot with the raspberry pi, I own several of those touch-screens. They are nice. I'm *just* starting megasquirt. (Literally today I got my first sensor, a temp sensor I had lying around hooked-up and "calibrated".)
I got the os loaded, java dependencies installed and installed the TunerStudio package. Was pretty easy. The screen is tiny! but I think it will work decent displaying just a few critical gauges; AFR, RPM, Boost...
The challenge will be powering it from the car. Actually that is the easy part, it will be gracefully powering it down when going key off or similar to not corrupt the os. I think this can be done over the GPIO pins.