This will make you lot unhappy from the sound of that IBC thread. In our pushy feather, Hellbringer, we had a 80mm computer fan with 3 rather bright LEDs in it. It was such a nice fan as it moved more air then my brothers desk fan. Anyway other then the lights on the IFI Victor 883s and the Volt Watch it was the only lights in the robot. It was also mounted on the inside surface of the robot with a 80mm dia hole to allow the air though and made it very visable.
Now for the bit you wont like. The fan was under the robot. With 10mm of ground clearance it caused a really nice red glow from under the robot. Everyone knew the robot was on. Do neons as we call them counts as power lights?

Why does the rules say Surface mounted rather then Clearly visable?

Im Australian and I dont think Ive every read any rules all in one sitting so you can ignore me if you want.