Hi Shaun...by way of a cheaper contrast...i have a Shimano 600 Arabesque headset [the scalloped one with the Y engravings] in virtually perfect condition for £22.50 posted....now sold anyway.
Well Swatan Vulan also has a 600 headset with the funny lock nut (anyone know where to get the tool for that, I am a sucker for tools). Dunno know how much he wants for it.
Also Shaun the NOS 7400 headset are JIS only and are £50 but the 7410 headsets are cartridge type and have a 26.4mm crown race. They are £70 unfortuatley. They are new though well new old.