Ha....ok, that got me wondering, which lens length would be closest to 201 mm.....I did not have to look far, the 70-200 f/2.8 III is 199 mm.ha ha that's an 8inch big telescope! (although this has 200mm real glass diameter and its materials increase this) but still 20cm (OK 22cm) is almost the length of the 400mm DO II lens!!!!!
But, that seemed off to me as I own the 500 f/4 II, so I just started playing with it and the dimensions I am quoting from TDP seem to correspond more to the lens hood than the actual front element. I measured my front element to be ~5.8" or 148 mm. TDP lists it at 170 mm or 6.7". That is about what I get for the lens hood to the actual knob on the hood or from the barrel to the bottom of the foot.
But, yeah, this is a big lens. But, honestly, what will keep me from buying one will be the price point.