diberry - 3:35 pm on Nov 8, 2012 (gmt 0)
I just looked at my stats: 50% of G referrers come from page 5,7,9 and 10 (#52,#76,#91 and #101). Never seen visitors come from pages so "deep".
I've been seeing this recently, too. And it's not always for long tail phrases, either - it's like people are just going through a lot of pages to find what they want.