Some things I would like to see are pedal controlled devices. Something like a pedal controlled wheelchair, not powered by the pedals just control the forward and back motion. My mother with sever arthritis can still pedal but has a very hard time walking. It would be a little exercise doing something that needs to be done (getting around). A pedal controlled remote control lawnmower would be nifty also.
Where I used to live an elderly gent rode a very low to ground bike. Looked a lot like the silly motorbikes some peeps do. I imagine they’re out there for sale.
many ebikes work this way, pedaling and the chain more or less signal the motor rather than provide meaningful power... though afaik none of them do backwards for obvious reasons
she might enjoy an etrike, though more for recreation than normal day to day
Have you seen what people are doing with hoverboards + wheelchairs? Carer- & user-operated variations. Not professional solutions, but certainly fill a need.