There are body shops that can professionally apply writing or even designs on cars.

I was thinking of having them put the word H Y B R I D in big letters on the back of the trunk lid.
Of course that metalic Honda "H" thingie will be in the middle of the word.
If you make it the right color and font it may look cool.

Need fewer troops to support.
Drive a hybrid.
Best tank 71.65 MPG.

Before this car I spent two years learning hypermiling on my 2004 HCH1.