1) Located the first reference to "silk road" on the internet. You can find this yourself on Google: "silk road" site:shroomery.org Date range: Jan 1,2011 - Jan 31,2011 *
2) The same username, "altoid", showed up on a bitcointalk days later.
3) Later in 2011 "altoid" made a post on bitcointalk with his email address, containing his real name, in it: https://bitcointalk.org/index.php?topic=47811.msg568744#msg5... If you search the name on Google it doesn't show up, but if you look at the user's page you can see it in his posts.
That seems like more than enough for a warrant for this individual. Everything after that should be easy.
I've used Google before to locate when a particular word or phrase first appeared. Kind of surprising someone didn't figure this one out quicker.
* Obviously this is a common word, so either adding other keywords with it would be likely.