I'd have to imagine that the whole caliper crosses with some other -bigger-US avalible bike. Like a CBR of some year....Heck, my bike has CBR929 front calipers on it, and man do they grab much different than my neighbors 929 does! Must have something to do with the NSR's weight?
I'd start by looking at what bikes NSR rear pads work on, and go from there. Someone probably knows something about it already though... I may even have one in my spare parts... But I'd have to dig to see...

Steve
_________________
MC21
04 NSR50R
93 CBR F2
98 CBR F3 track bike
95 VFR750
89 FL400R Pilot
90 FZR 4/600