To my understand, what Google does, is stack the page rank and relevancy of similar (yes, even spunned ones) into the article it think is orginally. So say if you submit to 1000+ directories, good chunk of that will be deindexed and put into supplementary results, but no worries, their page rank and relevancy score will goto one of the larger sites.
As an article directory owner, I bookmark sometimes articles I receive, and I notice this trend too, and have created a lot of
PR 3+ pages on my site :-D Submitting the same articles to thousands of sites can only rank your site up, otherwise, it would be so easy to knock down competitions that it's not even funny.