(shot by D700 + Zeiss Makro-Planar 50mmF/2 ZF @f11)
I finally made it, its MFD is 1.3m better than I guessed. With added helicoid (16~26mm) its MFD becomes 0.45m.
Put 2mm thick ring between the lens and body, it can focus from 1m to 3.2m. It's very good for portraiture shooting.
(The lens was bought $150 @2006 in Tokyo for this modification, but better looking than my already scratchy S90.)