I can see that twitter itself must be resolving any shortened URLs somewhere, because if you search for a domain name (such as amazon.com), you get a bunch of results that don't seem to match until you resolve the shortened URL in the tweet and see that it points to the domain you searched for, which is fantastic!
However, I am wondering if there is any way to get those resolved URLs from the API, or (better yet) if there is anyway that those URLs could be exposed in the search results themselves. Currently, I am resolving the URLs myself by requesting the URL and saving the resulting location, but that starts to take a while when there are a lot of results returned.