Update:

It took about about 3 weeks to set up and fund the IRA LLC.  This was an intense period of research, phone calls, printing, filling out, scanning, and emailing forms, overnight mail, trips to notaries, trips to banks, record-keeping, and steering around all the roadblocks that popped up along the way.  The power elite do not want this to be easy!

It took about 6 weeks to purchase the bitcoins.  I decided to use only U.S.-based exchanges, so that if anything went wrong, I could sue them in a U.S.-based court.  CampBX flaked out on me, so I wound up doing all my purchases through Coinbase.  Their buying limits were a major obstacle.  Shortly after I bought my last bitcoin, they announced that my purchasing limits had been raised.  Wasn't that super of them!

So about 9 weeks after launching the project, during which time I spent about half of my waking hours on the effort, I finally had a nice nest egg of bitcoins in an IRA LLC owned by my Roth IRA. 

I'll be 59 1/2 in a year or so, after which all withdrawals will be tax- and penalty-free!

Now I'm just waiting for the price to go up!