Sorry about the thread creep back to logo lights, but just a quick reply to the comments about marketing. Sure, on final approach or T/O close in to the airfield, punters on the ground can see your tail/ logo. On the ramp at the majority of airports that I visit (both UK and abroad), the ramp is so well lit you can see the whole aircraft and all it's paint scheme without the logo light on..... another way of saving bulb life and hence costs.....
PP