Automatically adding newpage to posts

Our current CMS automatically determines where to drop page breaks on long articles. I know you can embed <!--newpage--> into a page to split an article into pages, but is there anything that will do this automatically when an article is displayed?

On a similar topic, secondary pages have weird URLs in WPMU. It looks like you can have a ...mypage.html and then the second page is ...mypage.html/2, which just seems strange. Is there a way to configure WPMU to make that ...mypage01.html and mypage02.html instead?