I built a Yost Sea Ranger with a heavily modified deck to give me lots of knee room and foot room.
Frames are aluminum bar, deck beams are aluminum rod, while gunwales, chines, and keelson are western red cedar.
Dimensions are 17'8" by 20"
Weight, fully rigged, is 26.6 lbs.
 
The aluminum rod deck beams were not totally successful, as they bent under the load of the stretched skin, but I was able to achieve a high curved foredeck with a very light boat.
 
The design has far less initial stability than the Black Dog Greenland kayak. I need to spend a few days paddling in flat calm water to get used to it before I venture out on the bay, or even a large river.
 
More details can be found here: http://home.comcast.net/~buyerj/site/?/page/Sea_Ranger_LC_High_Deck/
 

Thanks Joel. I had fun experimenting with the aluminum. I think its a very viable way to go, although I do have some minor problems to solve.  I'm glad you said it looked like a wood-stripped boat at first glance. My goal was to have a finish that looked like amber varnish, and apparently I succeeded.  
 
Black Dog Sea Socks come up occasionally on a variety of other forums. Perhaps you are the only people making them!
 
Besides the 2" narrower width to the boat, I think what I am feeling is the boat shifting from side to side across the Vee-shape. So I need to learn to balance on the Vee. I'm sure, given time, I'll master it, but I'm very glad I started with your Greenland design first to get some experience. The Sea Ranger would have been nearly hopeless for me as a novice.