There was a French Cyclo company and a British Cyclo company. The British company somewhat copied the French company’s designs, and became the dominant supplier in the UK in the 40s and 50s. Backwards, bolt-on shifter, friction, and cable pulled. 4 speeds.
A Steampunk artist could connect this to copper tubing and a steam generator to increase the shifting time by a second or more.
Bolt-on, top tube lever and a Simplex suicide shifter.
Campy Super Record 11
This one goes to 11, made with titanium and carbon fiber. This is a derailer you sacrifice yourself for in a crash.
Looks like a part that fell off of Robocop’s suit and shifts like magic.
More photos on Flickr.