Jira Agile already includes this functionality for Software Development projects. A Board is created for these projects which exposes issues in this kind of interface.
Why isn't http://gitlo.co/ getting the attention it deserves?
Isn't this just jira?
This is not Trello.
Bitbucket actually has http://www.bitbucketcards.com/ btw, http://gitlo.co is cool for github issues