Nikon make some nice lenses but none of them come anywhere near their S2 equivalent.
I guess Nikon shooters must be lucky to have access to the excellent pool of relatively cheap Leica R and Zeiss ZF lenses then.

Frankly, it is pretty crazy that even the 280mm f4.0 APO Leica R, one of the best lenses ever designed and one that is the object of a good deal of speculation these days, is still cheaper on ebay than the cheapest of the Leica S2 lenses new.
Cheers,
Bernard