That reminded me to answer the origional question. We used to have the junky strobe visor lights that noone could see except the guys in the car with them (and they were blinded).

Now we have led lights built into the interior visor that are covered with a small tint strip so you can't see them from the outside. Those suckers put out so much light that if I was behind you wouldn't know that the car didn't have an external lightbar. The real nice thing about them is that they have flashback guards so I'm not blinded and they don't roll across the dash like the kojak lights.