Wheelchairs tend to be heavy and pretty bulky, but why not take advantage of this shape factor that’s designed primarily for stability?
Here’s one idea I thought up earlier.
In an electrically driven chair, there’s room on board for all manner of useful stuff. Today’s invention is to equip wheelchairs with battery-charging facilities for mobile phones and wireless hubs providing extra bandwidth that can be rented out to other members of the public.
This would make those disabled people who chose to carry a suitable sign, a source of some very valuable (but hard to steal) resources. It might also encourage communication with people who sometimes find themselves overlooked.