I was thinking of having stacked mirrors, the way tractor trucks do. But your comment made me think: is there a way to have a flat mirror turn transparent, revealing a curved mirror behind it? You could activate the transparency just by using your turn signal.
Bigger vehicles such as buses often have a large flat mirror and a small half-globe shaped mirror attached to them. This provides proper distance and gives a nice wide view when you need it.
I would prefer cameras, but I am not sure if they are still not legal in the US.
