: Once you get away from the now standard keyhole cockpit there are few
: standards for cockpits in size nor shape.

Our local sea kayak emporium stocks seven sizes of spraydeck for seaboats,
from Ocean 1 (23"x18.5") which fits classics like the Anas Acuta, Ocean 2
(25x19) and Ocean 3 (27.5x19) through Keyhole 0,1,2 and 3 (which suggests
that there is no standard for keyholes either). I use an Ocean 3 deck
on my commercial fibreglass boat, which I consider to have a keyhole
cockpit - it's certainly bigger than I really like ... I built my own boat
with the same sized cockpit as the Anas, so I could use off-the-shelf decks,
but 20x16" is smaller than any off-the-shelf deck I've seen.

Both Knoydart (the shop, who do decks in Chillcheater, neoprene and nylon)
and Reed Chillcheater themselves will build custom decks to fit any cockpit
if you send them an outline. I got a deck made for my 5/6 scale Great Auk,
which has a long but narrow cockpit unlike any commercial boat. No doubt you
can find similar in the US, or make your cockpit to a size for which
off-the-shelf decks are readily available.

I like to have the same sized cockpits on as many boats as possible, so that
I don't spend half my paddling time looking for the exact deck to fit today's
boat :-)

Andy