Ask HN: Extracting the Twitter Social Graph

I have an idea for a webapp, but I would need a local copy of the Twitter social graph to make it. Any suggestions on the easiest method of getting it?

Originally, I thought of creating an app, or using 80legs, to crawl Twitter's social graph API. But even if I were whitelisted (which allows 20,000 requests per hour) it would take months to finish. So instead I was hoping someone has made a CSV or database dump of a copy of the Twitter social graph, but I haven't found anything online. Is anyone aware if such a thing exists?

Surely someone else has had this same need. How did they go about doing this?