Max Number of posts, authors, tags and categories


I am planning to make a site for which I need experts opinion, please consider the scenario as follows

site will be having millions of posts, millions of tags, thousands of categories and thousands of authors.

how would you see it performing within wordpress ? I am looking for optimized solution to get it done, permalink structure and nothing else is finalized.

I haven't even registered a domain name for this yet, so it's kind a very early stage question to decide whether to consider wordpress or any other cms for this site, or may be any custom coded cms.

Beside this, I dont think there would be any limit on number of posts,authors,tags, and categories on papers, but after say 500,000 posts and like 100,000 tags, it can be assumed that the site would be extremely resource extensive and would requires lot of cpu power and may also result in frequent wp_post table/database corruption.

please share as much of your opinion / experties and knowledge as you can.