I attended the Great Lakes Small Craft Symposium in Saginaw, Michigan this past weekend. There were only a few wood kayaks there, the rest being primarily wood canoes and sailboats. A company named Grand Traverse Boatworks had a couple of kayaks there, one with internal bungees but no 'scupper' notches to lift up with. After inquiring as to how they opened, the builder pushed down on one side, and the other side popped up. He had used foam gasketing that was a good 1/2-5/8" thick -- this made for plenty of room to push the cover down, popping the other side up. The only problem was that the hatch was a bit sub-flush, but this could be tweaked. I'll post a picture of the kayak soon, but I didn't take a close-up shot of the hatch. Funny thing about this kayak -- it was 19'x21" and looked very suspiciously like a Guillemot Expedition -- but it was billed as their own design. Same overall shape, same coaming, same soft chines...

Dean