My blog got PR6 with only around 5 articles and as far as I can tell, only 3 backlinks. Might've been a fluke but being linked from very few high-PR sites might help your PR more than 100x low-PR links. But, I'm no SEO expert at all! To be honest though, I'd rather have a PR3 site with great content and tonnes of traffic buzzing around it than a PR6 which is pretty much dead on it's feet.