Interesting and original-ish. But practical? Can't say.
Here's a suggestion I'm going to throw out there.
Instead of driving the wheel(s), use the propellers. When landing, at least two of the propellers pivot up and drive it around.
(You could also be clever and pivot the motors up about 60-degrees, so that there is forward force and an upwards force that 'lightens' the unit. And then you could drive the two stationary motors at slow speed to further 'lighten' the unit.)
That way, you don't need another motor to power it on land, and also you could put floats on it, so it would work in the water as well as on land.
That'd be incredibly inefficient. It uses a single brushless motor to drive the wheels which you're driving directly. You'd have to run at least two motors for the props and it's unlikely you'd generate enough thrust to move nearly as well as a single direct drive.
A 2200mAH battery is already going to have limited run times in a quadcopter; trying to use the props for the wheels too would just make that worse.
That is true -- propeller-driven cars are not so efficient, but for something this small and light I don't think it would make much of a difference. The thrust to move it on wheels must be a tiny fraction of the thrust needed to lift it.
On the plus side, you could do away with those goofy wheels. Too many parts (18? 18!) and I see tiny little gears prone to binding with the slightest bit of dirt. And just a single wheel is driven.
Also, the wheels being directly in the airflow of the propellers can't be a good thing.
Of course, to use the propellers on the ground, you'd need a mechanism to rotate the 'propeller pods' up. I think using the thrust of the props themselves to do this, with a micro servo to lock them in place, would accomplish this without adding much weight.
And if the propeller motors can be run backwards (I don't know offhand) then you can get rid of the steering mechanism as well.
Here's a suggestion I'm going to throw out there. Instead of driving the wheel(s), use the propellers. When landing, at least two of the propellers pivot up and drive it around.
(You could also be clever and pivot the motors up about 60-degrees, so that there is forward force and an upwards force that 'lightens' the unit. And then you could drive the two stationary motors at slow speed to further 'lighten' the unit.)
That way, you don't need another motor to power it on land, and also you could put floats on it, so it would work in the water as well as on land.