IMO, you're barking up the wrong tree, for several reasons.
1) There's a strong opinion among car drivers that roads are for cars, not cyclists. The problem isn't that the drivers don't know what the appropriate distance is, it's convincing them to provide it. A bully in a car will continue to be a bully as long as (s)he thinks (s)he is going to get away with it.
2) For the few who sideswipes cyclists by "honest mistakes" it won't help much. When the car gets close enough to pass, the lines will be hidden from the driver's view by the hood/bonnet. When you need it the most, it's not doing anything.
The only good thing I can see from this, as opposed to any regular rear light is:
- if the lane marking light make riders feel safer, then more people will ride. With more people riding, cyclists becomes a more accepted part of the traffic scene. And with greater acceptance comes less risk and less bullying.