Analogue MPG display using an OLED?
 

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!!

Here is an arduino color graphics shield:
Liquidware Antipasto: TouchShield: Bitmap Bouncing Ball

You'll get a lot bigger display for less money with a monocrome version though:
Arduino playground - GLCDks0108
http://www.arduino.cc/playground/upl...0108-small.jpg

And of course you can use a real analog gauge and drive it with pwm:
(This is a vpw obd mpg gauge using an avr processor and a sunpro tach)
http://www.circuitcellar.com/avr2004...05abstract.pdf

Ah, wicked, thanks for that. I have a blank in my dash so I'd like to take advantage of it and keep the factory look.

Great idea for a "real" gauge- I'll need more than 40mpg full scale on the gauge though :)