Both cameras have similar proportions and similar levels of build quality (although I'd give the edge to the D200). Here you can see the D200 beside the recently announced direct 12.8 megapixel Canon EOS 5D. Remember that the camera is only as weather proof as its weakest link, this includes the lens mount and only a few of the more recent Nikkor lenses have rubber seals around the mount ring. Nikon don't claim the camera to be waterproof but it's certainly more 'weather proof' than the average digital SLR. Just as with the D2X there are numerous rubber gasket seals around body seams, controls and compartment doors. Around at the back the D200 has the same oversized controls as the D2X which make it easier to use normally but especially when wearing gloves.
It really feels like a solid brick with no creaks or hints of flex. You can only really appreciate how well put together it is by handling it. Construction is much the same as the D2X with the same high quality magnesium alloy body, soft rubber coating around grip areas and rubber seals around compartment doors.
At first glance the D200 does look quite similar to the D100, but the more you examine it the more the newer Nikon design cues become obvious and you realize the evolution of changes since the D100 will serve this camera well.