Well I was in my local camera store today and decided to look through the Nikon accessories drawer. I was looking for the old style Nikon eyecups for a possible match for the D200.
I remember that Nikon has manufactured many styles of eyepiece attachments over the years and found several combinations that will work on the D200 (since I DO NOT like the eyepiece that comes with it).
If , like me, you like a rubber eyecup, find a Nikon part number EPOI 2370 (Erinreich Photo Optical, Inc) from old stock which adapts from the rectangular eyepiece on the D200 to an aftermarket screw-on rubber eyecup.
Or if you can find old stock circa 1993 rectangular Rubber Eyepiece SKU #0 18208 02939, it will fit directly onto the D200 without an adapter (see photos below).
I found a few , so check your local camera shops for old stock ... there's a lot of treasure in those old drawers........
I'm delighted to have found an eyecup for my D200 and I hope this is of some help to anyone wishing to put a little custom touch to theirs.