I apologize for not answering your original question, but I would not ever recommend a Zing Case for an investment like the D200, especially with hte MB-D200. Neoprene type cases protect only from light bumps or scrapes and pretty much offer little other protection. I would stick with a case that has dense foam, not neoprene.
I can't help with the original question, but I do use a smaller Zing-style neoprene case for my D200 without an MB-D200. As long as you appreciate what it will do (and not do), I find it to provide a useful degree of protection against scratching and gentle knocks. I tend to put the camera/lens in this case when carrying it in a non-photo backpack along with other gear. Works well
I agree that the zing case will provide limited protection - I am primarily looking for a zing case to wrap the camera in when it is outside of other bags that I already have. I live and shoot in a semi-arid and extremely dusty area and just need something to keep the camera covered when on dusty trails and dirt roads.
I have a Zing for my F5 and will order one for my d200 for the reasons above. It keeps out dust, sand, grit and mist. I keep my F5 and d200 with a 50mm prime (as a body cap so it's always ready) attached and can grab them from my large padded bag and run. The Zing just makes sense.
Per B&H's Zing fitment list, the large size fits the N90 so it should be the one for the d200 w/extended grip. The pro would be too large; that's what's on my F5 and it's tight.