Ok so I am thinking aloud - I have not even got my MPGuino working in the car yet!
It would be very neat to have a small colour OLED analogue MPG display on the dash and this may be one solution - a 1.7" colour screen:
Glyn > 4D Systems Smart All-In-One LCD & OLED Display Modules, LCD and OLED Graphics Controller Modules
An advantage I can see is that it's an ergonomic improvement and so a safety one. I believe it takes fewer human brain "cycles" to process an analogue (sorry analog
) display compared to a digital one.
Just an idea - I have no idea how to implement it yet!!