I looked into this for my old N6.0, I couldn't get hold of the stock wings and so was going to build some to turn it into the ultimate med cruiser when I was out in Cyprus. I moved to Germany before I could make it and sold the boat.
The design I was going to make required long teflon inserts into the beam ends (which I was going to lathe up) with a hole milled through the centre to take the wing insert. The wing itself was going to be similar to the Hobie Tiger wings:
http://www.hobie-cat.net/download/catalogue/gb/wings.pdfWhich I think are a fairly good design, although you need to keep the boat flat to stop the lee wing dragging -esp in waves.
