Light switches that light up when off

"Locator Switches Locator switches illuminate when they are in the OFF position, to help you locate them in the dark."

Our old, several additions, wacky electrical wire layout, home has several light switches that are not located where you'd expect, not near the entry way or entry door to the room.

I think light switches that light up in the off position would be a good idea??? Is this an easy DIY project?
One of the switches is on a sliding dimmer switch. Is that one doable?

 

Said switches are still made today although, I would find an NOS made in US or Mexico though as the new China made ones the neon indicator lamp does not last as long as the good made ones).

Be warned though they are made for incandescent lamps only though as the switch "sinks" a small amount of current though the filament not enough for it to glow but enough to light the neon indicator lamp that is why when the lamp is burned out or missing the switch is not lit.

This small current flow may make an LED or CFL lamp flicker or dimly light.

They are easily wired though as a standard SPST switch the older mercury switches with the neon "Locator" light are the best quality ones available not made anymore due to the mercury "hazard" not really as hazard as the mercury vial is sealed and inside the actual switch but oh well.

Edit:

I have not seen dimmer versions but that does not mean they don't exist just I have never seen one. Only SPST and 3-Way ones

 

Thanks, a lot of good information.