I have done a bit of work on this. It turns out that a share of YARR for any less than 1.725 BTC is the best deal anywhere, short of investing thousands of coins directly with pirate and putting thousands more in cold storage. The thread also looks at PPT.X bonds because they are also partially insured.
https://bitcointalk.org/index.php?topic=96092The flip-side is that the current prices are too high; you can get the same risk and a better return by investing sans-insurance.