Getting a 10ft dinghy out of a 4x8ft sheet is simple but clever, (wish I had though of that).  My take on a non-stackable would be to make it symmetrical bow & stern, even simpler & better load carrying. 
One question, does a double ended dory need much (if any) rocker?  A flat gunwale would make it sit upside-down on deck better.
As this post has become more of a general discussion on dinghies (should it be re-titled):
I have been looking into skin-on-frame boats.  I started in my teens with a grp slalom canoe, though always fancied a Greenland kayak.  There is lots of info on skin-on-frame kayaks, including some amusing YouTubes of the hull being attacked with hammers and various implements - so they are sure tough. They say they are less expensive and quicker to build.  There are also designs for dinghies, see http://www.gentrycustomboats.com/
I would be interested to know if anyone has any experience.  David had a wee black one, though I believe no more?
Cheers