This man might know what he's talkin 'bout. Short the 30yr bond futures and you may get seriously paid. Playing with 2x ETFs like TBT will screw you long term, but can be OK if you get some luck with the timing. If you size a futures trade appropriately it will perform much better (altho most people can't trade futures in their 401k etc.)
If it wasn't for paying the interest and coupon, you could short the long and short double etfs and make money regardless of what happens to rates. These are terrible at tracking and lose in the long run.