Originally Posted by
CliffordK
Thinking of the same concept, the "tri-hauler" made by our local coop is essentially foot steered. One does use the hands for stability, but I doubt it would be necessary.
Cargo Bikes & Human Powered Machines
I don't think they are making many bikes now, but the concept could be copied to make a custom trike.
Shifting might be an issue, but there are "autoshift" systems available, or perhaps a foot shifted (although foot brakes would also be important).
I normally advocate enclosed footwear when riding any open-frame vehicle… but if you've got no hands, toes need to substitute! On that basis, one thought is that if the pedal were extended a bit, you could incorporate buttons for controlling electronic shifters on the pedals that could be toe operated. Slip rings could be used to convey the signal back to a controller that drives a servo motor for pulling on the bowden cable going to the shifters.
Replace the seat with a more "bucket"-style seat to reduce the chances of the rider "falling off", and that could be a good option for someone without upper limbs to commute on.