can you use a lathe? (Or do you have a friend that can help?)
Take the whole Norton front end Sliders and yokes) and get a set of 35mm forks that have double damping, something that is straight, has the right amount of travel, correct length tubes that are straight and in good order. Betor, Husky, Marzocchi Something Japanise (early CR125 for example) there is plenty to choose from.
Spin the sliders down to go in side the Norton bottoms then modify the tubes to have taper tops to match the taper in the yoke. Stuff it all in and away you go. (there are so many different ways of doing this, weld the assembly in, turn a thread in your modified slider and screw it in, hide the whole lot behind the Norton seal holders if you want etc etc etc etc.
Whilst you are modifying the tubes turn a thread to take a set of my large head Ceriani fork nuts (shameless plug there!) and then when you slide the tube into the top you the nut will hold it all in place. Or just use the Norton style nut then it will look less obvious if you are worried.
The end result is a set of forks that work (better damping etc) and externally look the same. You can set the height / travel etc etc whilst you are fitting it all together and modifying it.
This is not a 5 minute job and you need to know what you are doing. But it has been done a million times before.
In OZ you may call this cheating but in the UK it is standard practice. Miller did this a million years ago on his HT5 with Betor innards and every man and his dog has followed.
(I can hear people reaching for the Oz rule book muttering......... Discuss)