This would be like a "Big Wheel" kids toy vehicle that has a gear box with an adapter that allows a cordless drill to be the power plant.
There can also be a variety of other applications, such as:
a utility cart that has a gear box with an adapter that allows a cordless drill to assist in moving heavy loads
a winch that has a gear box with an adapter that allows a cordless drill to power it
a garage door opener
a chair lift (that helps people get up and down their stairs)
I think that a lot of things can be powered by a strong cordless drill, I'm sure more ideas will come to me.