Autocar has reported that Lamborghini will not make a rear-drive version of the Aventador. Apparently this is mainly due to the state of the art of the control systems that is on the car. With the Aventador's nearly-700-hp output, Lamborghini believes that that is simply too much power to be delegated to the rear wheels effectively.
Is Lamborghini taking a direct stab at McLaren and Ferrari? Each of those companies makes a stupidly powerful rear-drive supercar, but there also don't seem to be problems there. For right now, if you want a rear-drive Lamborghini, your only option is a Huracan. Not that there's anything wrong with that.