Bernie, I like to use fuel dots for the filler. They do come in colors. Maybe they are not hidden but they blend well. I saw a giant scale that had a neat switch the other day. It just had a small hole in the fuse with a wire sticking out. On the wire was a red flag that said"remove before flight". It looked very scale. When the wire was pulled out the connection was made and the plane had power. When he pushed the wire back in the power was off. It had one on each side of the plane. One for the ignition and one for the RX. The guys over in the giant scale forum could tell you more I'm sure.

David