In reply to Scottish:
One of the biggest ones I've seen (6 feet) is on a route called "Mirage" in Australia's Grampians, it's notable due to its height above the ground and the grade (27.
Photo 3/4 of the way down this page:
http://www.chockstone.org/Interviews/SCarter.htm
There is also a Simon Carter image floating around somewhere of the whole sequence shot from side on which is very impressive.
Superb rock, high on the cliff and a solid crux dyno. nice route