Had a friend who lost a leg to a rocket attack on a truck in Vietnam. He used to use the prosthetic to chock the wheel on a race car. Later, we built him a prosthetic with a sapling wrapped in a vine, like the popular canes. Eventually, we made a set of controls for a Sportster that let him operate the shifter with his right foot, and built a peg for him to put his prosthetic on. He wanted me to build him a prosthetic with a concealed 12 gauge side by side in it, but I'm not sure the BATFE would have been happy about that.
My brother has been battling issues with one foot for the last 8 years, Type 2 diabetes. He thinks they have it resolved this time. He's 73.