I also looked into the fore/aft adjustability of the Berthoud saddle as some noted the plastic cantle piece seems to be bigger than what is on other leather saddles. I looked around and found this though:
http://www.flickr.com/photos/wallblo...n/photostream/
They are saying that the rails on the Berthoud seems to be longer than the one one used on Brooks saddles. From the pics, it looks very similar, but at lease they don't look shorter than the Brooks rails....

Chombi