A good question is how a paired-trade of long these stocks and short these bonds could go wrong.
The "crash of some sort" that would concern me most is some jump in stock volatility - scaring people out of stocks and into bonds. Exactly the opposite of what you want for that pair.
That said I like the idea, provided you can short bonds. (But why not - borrow them and sell them just like stocks.)
ij
It is astonishing what foolish things one can temporarily believe if one thinks too long alone ... where it is often impossible to bring one's ideas to a conclusive test either formal or experimental. J.M. Keynes