I was thinking about this thread when I recently told a representative of Fidelity's Portfolio Advisory Services that I'm not unhappy with them, but I want more exposure to bitcoin in my Roth IRA, and Fidelity doesn't seem to provide a way to get that exposure, so I'm transferring a portion of my funds to a self-directed IRA LLC.
I could have saved a bunch of money in taxes if I had learned earlier that it is already possible to invest directly in bitcoin in retirement accounts. We don't need SecondMarket or the Winklevoss ETF. For about $1500 and a modest amount of effort, anyone can set up a self-directed IRA, which invests in your own IRA LLC, which invests directly in bitcoins.
Soon I'll have bitcoins in my Roth IRA, growing completely free of capital gains taxes. And the side benefit was that I politely told Fidelity that they are losing actual business by not providing an easy way to invest retirement funds in bitcoin. If they turn around and start a bitcoin mutual fund, I'll be expecting a lot of you to be thanking me!
More info on self-directed IRA LLCs at
https://bitcointalk.org/index.php?topic=396783.0