There is also a company called Kehler Skis. They make certified nose and main gear skis for 150-172-182-206 and caravan.
They are (keshing$$ keshing$$) quite expensive...
I tought also of copying a NA-800 because they are so rare I don't think I will manage to find one soon, and its not something impossible to copy. A friend of mine has a die to make Tunnel and also the main boots, he did and sold several Federal 2000 and 1500 copy over the year...