Just found this, looks like an interesting idea, just not sure how much kit you could carry in it. Maybe some of the resourceful chaps on here coming up with a similar design and try it out as this one is a one off so far.
http://www.wired.co.uk/news/archive/2011-07/29/folding-canoe-backpack
http://www.wired.co.uk/news/archive/2011-07/29/folding-canoe-backpack