HeadsUpDisplay that shows ICE on /off for G2 Prius ?

Is there an aftermarket HUD that is able to show when the car goes from ICE to EV ?
If not, how hard would it be to hook up a dash mounted LED that comes on when the ICE is on ?
I can't always hear or feel when the ICE is on, and this would be a non distracting way to know.

I'm posting a lot recently, so instead of creating another thread, I'd also like to ask what you guys prefer for a MPG gauge, and why.
The ScanGauge, or something else ?