I don't know about ailerons, but FMA Direct's Mini Skysprite uses a tail mounted motor as a rudder. It is suprisingly responsive, and supposedly weighs less and takes less power than a servo or mini actuator. However, this is really only practical since the motor is so small that it spins up very quickly in either direction. It's a great little plane for $40.

As for larger scale, I think that it is a cool idea, but would have trouble making it through. Who really wants to buy extra motors anyway? I know that if we are looking at a .40 size, it would end up being either simple one direction thrust, or maybe a more complex but heavier tail-rotor system, but in any case, I'm guessing that the motors would be brushless outrunners, each requiring their own speed control which comes to about $200+ at the least. Also, wouldn't there be some wing aerodynamic problems inherent with a hole in the middle of a wing? It would be interesting if you get any extra lift if both are pointing down though...VTOL[8D]