Umbraco version (4.5.2)

I'm wondering what the best practise is for finding all unpublished documents, of all the available document types? I know i can do this directly in the db, but I was hoping there would be some kind of api call available for this, I suppose I could traverse the children of the rootnodes returned by the Document api, but that would be awfully slow for a lot of nodes.

Any suggestions are most welcome

// Anders