Done by a Romanian builder, based on Ross Leidy Kayak Foundry software:

https://plus.google.com/photos/117020649707486211092/albums/6066104030710950801?banner=pwa

More info on Kayak Foundry:
http://www.blueheronkayaks.com/kayak/index.html => Forums => Launchings =>
Polystyrene Strip Plank Kayak

(direct links are disabled on that site)

Not only a nice boat, but *sectional* too, for easy storage.

Looks like a nice project...
Here are some comments from the builder (from the BlueHeron forum)

The building with polystyrene is faster and easier. It's my first build. I had some wood but not enough so I was thinking why not polystyrene. I used hot glue. You can build the hull or the deck with strips of polystyrene in one day. It took me about 100-120 hours to build. With wood it takes maybe 300 hours.

Yes, 300 gsm is needed, the polystyrene is about 35 kilos per cubic meter and virtually has no resistance. But it gets very tough after fiberglassing inside and outside.

The weight of the kayak is 22 kilos without any accessories.

It paddles great.

Things I noticed:
Fairly heavy cloth (300g/sq m which is somewhere around 8 oz/sq yd ??) was used
Building time shows how much time can be taken with wood strips - I don't know if that 300 hour time is using staples or not; I generally take a lot less using staples.
Looks like drywall screws were used to help hold the foam to the forms
The builder figured out how to use hot glue with the foam and make it work.
22 kg is just under 50 lbs - for a sectional boat (heavy bulkheads) that's pretty good.