No idea, especially as pass phrases have become more popular the max length of a password that you might see in the wild has gone up quite a bit. Lets say someone is willing to type for 1 min to login to a site. According to Google the fastest typing speed recorded is 216 words per min. According to the words per min Wikipedia entry a "word"(They give examples of "I run" counts as one word, but "rhinoceros" counts as 2) is 5 characters long so that gives us a max password length of 1080 characters. According to wikipedia War and Peace is just shy of 600 thousand words long or approximately 3 million characters.
Therefore 1000 is a good minimum max length but 3 million is way to long.
Therefore 1000 is a good minimum max length but 3 million is way to long.