I ordered a couple of key chains from Billy at Knight Designs. They arrived yesterday along with the hardware for the seat extensions I ordered from him. He decided to start including the mounting hardware with the extensions after I had already purchased a set, so he included a set of the bolts with the key chains.
The key chains are plastic with laser engraving. They have a key ring and a plastic mount as seen on many rubber key chains.
Here is the front of the key chain.