jis bottom brackets work with italian square taper cranks too, only the cranks will sit 1mm out (don't go as deep onto the taper). my retro bike has late 80ies ofmega super competizione cranks (a copy of campag record of the same era), it requires 118mm bb (i use jis), outer chainring is at 47.7mm from centreline, crank arm clearance from the chainstays ~9mm, inner chainring from a chainstay - 3mm.
a similar setup would work (except i wouldn't want to use a square taper bb on a "proper" bike, but that is _my_ problem haha..)