Just an idea: Use a MU installation and give the blog names the names of the authors (use Sub-directories). This way you should get much closer to what you want to achieve with on board stuff.
This means that you’ll get your author names appended to the original domain and when you go there, you’ll see their blog pages = author posts.
http://example.com - main domain
http://example.com/hans
This solution would avoid any sort of programming.