NO! Let's stick with what at least theoretically usable in "real life"
Asymetrical ship isn't a bad idea only because of the inability to enter and effectively manoeuvre in atmosphere. It's a bad idea for many more reasons. Centre of mass is one thing, that can be circumvented (simply make the longer wing lighter, etc...) but that's a static centre of mass. Problems start to occur once the ship get to move.
Straight line is relatively fine. Acceleration is the first problem, because, as you know, we can accelerate into every direction (yay space) which means that in order for the sip to remain stable, it's centre of mass would have to be balanced and
at the same place for every axis. (aka the ship would have to be made "symetrical")
The real fun, of course would start once you'd try to rotate such ship. No matter how good it is "balanced", different lengths of the opposite sides of ship (along whichever axis) mean different angular velocities and therefore different momentum. That means that ship would never rotate around its centre of mass, so you wouldn't be able aim weapons while moving, there would be unnecessary strain on every part of the ship, and I REALLY would not like to be that person who has to calculate where to put the thrusters.
In short, however cool-looking and all that (I'm not denying that) it's a really bad idea and should remain in sci-fi books from 70'.