Google: AR book finder
There you find a tool where under advanced search you can search interest and book level...ar points will kind of show longer books (higher the points, higher the pages) but you can click on the book to see word and page counts too.
You can filter fiction, non fiction and a bunch of other filters too. They do give pretty good descriptions and some warnings about content (teen fiction for ten year olds is always tricky...I have a ten year old sixth grader too). The classics are what I am pushing...he has read all of Sherlock Holmes, some Jules Verne, etc.
