Whatever the contraption, could you take it around an obstacle course? To
my knowledge there's only one tricycle CAR in the world (it's British).
There's a reason.

I suppose it doesn't HAVE to be a car.
Honda makes a GoldWing trike that works just fine.

I'm pretty sure it's already been done. But there's a bit more to it than
just taxiing on the street. It needs to be safe on the street.

I agree. This is where I think the majority of ingenuity and design would
be required.

Adam
N7966L
Beech Super III