Has anyone developed a backlight for night driving similar to those used for
Navigator progs?

The backlight can be adjusted down, but is often too bright to use at
night where night vision is critical.

Note that in the nav devices and software, they don't reduce the
backlight, but, rather, change the screen colors to darker ones to block
the backlight.

Another option might be to look for some soft grey plastic sheet such as
that used as stick on sunshields.

Beverly Howard [MS MVP-Mobile Devices]