"Tail fin" suit for motorcycle rider?

[tallguy]

As we all know, aerodynamics plays a HUGE role in land speed racing.  I've seen some
aerodynamically-designed helmets -- even on bicyclists.

I've also seen some motorcyclist suits that have some kind of "hump" behind the rider's neck, to help "fill" the volume behind the helmet, where air flow would otherwise close in a fashion that is rather turbulent instead of smooth. 

Air flow around the rider's torso tries to close, typically in a rather turbulent fashion as well.  So I was wondering . . .

Has anyone tried wearing a suit that has some kind of "tail fin" shape that helps the air flow close again after being
forced open by the rider's torso?  Could this be helpful, or more like just an unwieldy, heavy hazard?  Of course, any
side wind would have more effect on a rider wearing such a suit.  I'm not imagining something ridiculously (and
dangerously) long -- such as 6 or 8 feet.  But if it's just 1 or 2 feet long, might it possibly provide a small benefit in
speed (say, an additional 2 mph?) -- without severely compromising stability?  I don't know what rules would apply here.  Maybe some experimental tests could make sense?