Mate, you aren't seriously comparing those images from digital secrets with a Nikkor 8mm are you?
They are not up to Sigma standards and because the D200 has a 1.5 multiplying factor you cannot get a full circular fisheye image with any of the "proper" quality fisheye lenses.
The best bet remains Sigma 8mm (Drum) or Nikkor 10.5mm (Full Frame) on the D200. If you are feeling rich the Nikkor 8mm or Coastal Optics lenses are the go but both would still produce (Drum) images on that camera.
coastal optics 4.88 mm fisheye would be a circle, thats the point of it, designed for a 1.5x sensor.
Not that I think it is that. You'd think they would admit it if it was anything so expensive as that or a nikkor 8mm with a relay system. Equally it seems strange that the agnos adaptor and a fc-e9 would count as a secret? For that matter how is this a d200 secret when presumably its applicable to any nikon dslr? Anyway not really important as people say but I am now curious.
The 1Ds is a Full Frame/Full Sensor camera unlike the D200, D70, D50 or Canon 20D, 350D etc.
Yes, you can get a custom grind full circular lens for a DSLR with a small sensor but it is not what you are seeing on the Digital Secrets article.
As for your dream set up the 1D MkII and 8mm Nikkor will still only produce a "Drum" image. What you really need is a 1Ds and Nikkor 8mm. Because the 1Ds MkI or MkII is a full frame/full size sensor camera. (Like Canon 5D and 1Ds MkI)
Well I emailed someone who mentioned having read the book. And hero that he is he actually told me. He didn't go into specifics but what it is is an fc-e9 with several step rings on a particular zoom lens.
The idea is that this particular zoom lens has less flex and can support the lens's weight. The step rings get the right distance to reduce vignetting and increase edge sharpness.
If you want to know the exact details I guess someone will have to buy the book. Don't think I will bother. Nice to have my curiosity finally satisfied though.