Everytime I search for a 63mm Nikkor lens, I get to this:

http://homepage2.nifty.com/akiyanroo.../apo/el63.html

It says it's a rare piece of equipment, but you who knows. You might be able to find one.

I use a 63mm F2.8 lens for my enlarger. It's undoubtly a real nice lens for printing, but I have not tried it as a macro lens so I don't know how it is.