According to the Le Mans Live Blog, Audi is working to unveil a new version of their Le Mans Peugeot killer on December 10th. After experiencing limited success against the French auto-making giants diesel 908 HDI FAP, it comes as no surprise that Audi wants their proper place on the top of the podium.
Of course it wouldn't come as a shock to those in the racing world. Audi has notoriously rejected the notion of a closed-cockpit Le Mans racer for years, even as the competition adopted the design to reduce driver fatigue and aerodynamic drag. But after Peugeot managed to knock Audi off of its Le Mans throne in 2009 with its closed-cockpit 908 HDi FAP, the German racing team's tune changed in a hurry.
Looking at the past, it won't come as a shock if the R18 is a closed cockpit variant.
Le Mans Live Blog is run by Michelin, who happens to be a close knit partner with the entire Le Mans program, more particularly Audi Motorsport, so maybe this is more then a rumor.
Sources: Le Mans Live Blog, Fourtitude