Yes there is such a category where planes are judged upon how "scale" they fly. There is a whole world of competitive flying that is dedicated to replicating scale flight... IMAC is not much different that pattern relative to scale flight. There is an organization out there that competes and judges planes on how realistic they look, and how true to scale they fly.. IMAC planes are WAY lower in wingload than the scale versions. They are Built to scale and they do emulate scale aerobatic competitions, but they are quite different.

Let me tell you something.,, Good 3D is HARD and I mean HARD to perform. If you can fly 3D proficiently there is not anything with wings that you cant fly well. All 3 disciplines (3D IMAC and pattern) are the extremes of aerobatic skill. There are other challenging things you can do with RC planes, but none more difficult to master than these.