Have bi-wings been used without creating more drag? As I understand from answers I've read here 1, 2, 3, biplanes create more lift with less wing span when compared to single wing aircraft, because the combined wings have greater surface area overall. 

However this is usually at the expense of added drag as both wings are accelerating the same air downwards causing interference and creating inefficiencies. Also the wings commonly have supporting wires/structures between them causing more drag.

With that said biplanes do have some desirable characteristics like shorter roll response. I also realize when looking at how nasa calculates for the drag coefficient, wing aspect ratio is a major factor in their equation:



With this information it would seem to me if you could separate the wings of a biplane far enough apart that they don't cause much interference, you could possibly get a better performing aircraft with the same wingspan. 

I almost imagine it being as simple as making the tail a full sized wing and giving each wing a thinner aspect ratio. However I've never seen this done before or even attempted. Is there a reason for this? Would the wings still interfere too much with each-other.
Moving the wings vertically apart would mean more and heavier supporting structure, but also a higher pitch moment of inertia. Since this grows with the square of the vertical expansion, a biplane with a lot of distance between both wings will be hard to control and very sluggish.

The real advantage of a biplane is reduced induced drag because less structure needs to be lifted. When cross-bracing enables the top wing to work as the compression member and the bottom wing to work as the tension member of a truss, a very lightweight structure becomes possible, especially when the size of the aircraft grows.

If all you have to power your airplane is a heavy, inefficient piston engine like those at the beginning of the last century, and you can tolerate that your aircraft won't fly fast or far, a biplane is indeed the lowest-drag solution.