Long Term 2014, 2015 options could be the best bet. Lots of upside leverage.
If you can handle some risk, then long term options could give you some excellent, inexpensive leverage. It will also make the shorts to cover faster. They don't want to be stuck with thousands of calls outstanding and no shares available to buy. A-la Wolkswagen sqeeze.
I'm short a large portion of the open interest in the way out of the money LEAPs. Easy money with very low risk. I also own tons of common. The 2015 LEAPs have very little risk and if there is a buyout I get to keep my premium much sooner.