The existence of multiple length chainstays for the S40 appears to be something of an open secret. I heard about the short chainstay on this forum and could find no reference to it on the Cruzbike commercial website. An email to Cruzbike got an immediate response from Robert explaining their availability. I was lucky and found a swap for a shortie on this forum. If memory serves, new chainstays from Cruzbike HQ were $150 -- which seems like a very fair price for what it is.