Hi!
Nope, no NOS, though rarely you may see one come up for sale on perhaps thesamba.com, it'll fetch a high price!
AFAIK, none of the parts are available to refurb, any repair kit is obsolete, I did kick myself for not buying a repair kit when i saw one last year, the buyer had a picture of a pile stacked high, but it was dear, and i had money in something else.
I think most so called refurb boxes are just a variety of other equally poor boxes with all the best bits slung together tightened up and filled with grease. Unless someone can say otherwise.....
There was a thread on here about machineing the pin a little, but as to long term longevity if the pin is specially case hardened is anyones guess, but I'm sure a suitable good 2nd hand one could well be machined and redone to a reasonable end result. Assuming they have the correct tools to set torques and all that.
My box is worn, still pass a mot, doesn't wander but has play, i have a good 2nd hand one from one of our Dutch friends. If this proves to be unsuitable after some time, there is a conversion which was covered in another thread, to fit a late bay box, which are readilly available, but this does require a little hole cutting and welding, but if the only other option is a crap refurb, well!
If you do find a NOS box, best buy whatever you can, and save me one please!
I'm on a works pc, so haven't got my list of links to hand, but the search function will find what you need.
Cheers,
Alistair