Ask HN: Getting an array of tweets that mentioned a given url?

As part of a project I'm building I'd like to be able to get an array of all tweets that mentioned a given url (including if it was wrapped in a t.co link or url shortener).

I run a url shortener service (vb.ly is now vbly.us) and when someone tweets a link 80+ bots come by immediately and 'unwrap' the url - so plenty of folks are building these systems (Most of them are on AWS and most don't have a recognizable user-agent or anything running on port 80 of their IP for identification).

Now I'm on the other side and wondering if I can tap into one of these services. Any ideas? Thanks!