VIX buy & hold strategy

Here is a simple buy&hold strategy that popped up while I was playing with  some VIX based ETNs . The volatility was extremely high through the end 2008- beginning 2009, presenting a good opportunity to go short on the VIX. A good way to go was probably the  VXX etn, however one would suffer some substantial losses through the summer of 2010.
Now take a look what happens if the upside risk of the VXX (short term futures) is hedged by the VXZ (long term futures). It turns out that a the summer 2010 dip can be completely 'ironed out' by constructing a pair of short VXZ-long VXX, allocating 2x of the capital to VXX.  The graph below shows a portfolio of -22 shares VXX,  46 shares VXZ. Sharpe is just above 2.

Of course past returns are not necessarily representative for the future, but I imagine that during the next crisis this behavior could be repeated.
At this moment this strategy may be turning around, as downwards potential of the VIX seemes limited for now. But I can't wait for the next crisis. ;-).