I implemented a brute force vxx-xiv strategy of the blog TradingTheOdds ( http://www.tradingtheodds.com/2014/10/volatility-risk-premium-trading-volatility-part-i/ , http://www.tradingtheodds.com/2014/10/volatility-risk-premium-trading-volatility-part-ii/, http://www.tradingtheodds.com/2014/10/volatility-risk-premium-trading-volatility-part-iii/ ), more as an exercise then anything else. However if we can remove some of the downside, add a hedge , it might hold for the contest. Although I would argue the the VXX is in fact a 3.4 hedge on the SPY so we might not want to hedge with SPY as it would exacerbate the effect when it goes wrong....
Anyway, I just love the vix and I'm convinced a viable strategy is doable ... this one is not good for the ulcers and heart-attack prone users
Peter