If you had appropriate endorsements, eg low flying, low level aeros or whatever it was, there really shouldn't be anything to stop you finding an appropriate part of a training area and practicing your display with reference to some easily recognisable ground markers to simulate display line and crowd centre etc, I'd have thought.
I fully understand your point of view, but where are you going to do this and how are you going to do it at low altitude? It's all very well do simulate it up high, but it's simply not the same come the day to perform. There are minimal low flying areas and you generally can't beat up your local field due to training traffic and the like. I'm not saying it can't be done, I'm saying that it can be very difficult to arrange and at many airports not a chance in hell could you get away with it.
Then there's the issue of you organise it, get permission, then some moron complains and sends his iPhone video to CASA. Sure you might be in the right, but nobody wants the stress of being counselled and being labelled guilty until proven innocent. The fun police have made it increasingly difficult.
I remember a AUF instructor from Mangalore years ago practicing in his Drifter for the Mangalore airshow. People would run into the flying school yelling out "some guy has crashed his ultralight" or "some guy it out there trying to kill himself in a Drifter." That was long before the days of video phones. One day the Police showed up after a number of complaints even though it was over the airfield.