Well, it really is just a ReadItLater to Readability importer. It only imports your unread articles!
This runs on Sinatra and requires a bunch of gems, as you can see in the source. Use it at your own risk, after putting your relevant keys into the environment.
I have this deployed on Heroku here: http://readability-importer.heroku.com
Known (or suspected) issues
The articles are not imported in order. This is because the article text is fetched by Readability asynchronously after we push the bookmark to them. Each article takes a different amount of time, and the order of articles is rendered reverse chronologically depending on when the article was fetched. Not fixable.
I am not spawning a background task to do the import. Thus, if it is long running, Heroku will kill the instance of the application, leaving you partially imported. Fix is to start a background job. Not going to do, since I'd have to pay for Delayed Jobs on Heroku. Not fixed.
I should make this obvious on how to use this locally so people can import from their own machines without the Heroku limitation.
This was an evening with Sinatra and OAuth. It could use a lot of cleaning up and beautification. If you want to help, you know the drill. Fork, change, pull request, enjoy.