Directory submission it is just one type of link building, but in my opinion it's still works. 1000 directories submission? It not looks naturally... It is better to submit 10 articles to EA, then 1000 to link directories. Usually I submit my new site to 100 directories in 1 month and taht's works for me, but again it's just one type of link building strategy.
Your multiple references to PR, your reference to PR 4, and goal of obtaining a single kind of link indicates that you need to slow down and learn the fundamentals before proceeding further.
There is much about your plan that is flawed. If you want your site to be in a happy place then I encourage you to forget what you think you know about SEO because it is holding you back, and start over by reading the link dev library. [webmasterworld.com] After you finish reading that you will hopefully have unlearned what you think you know and come to understand the true fundamentals.
My suggestion would be to forget about PR... Just because a site has a higher PR than yours does not mean it is getting more traffic, more sales or more ad clicks. PR is just one of MANY factors that are taken into account. Don't try and get a higher PR number just for the sake of it, concentrate on building traffic and converting that traffic.