I don't know the exact number but not many. I have owned/traded around five myself and still have one in the collection. They are beasts of burden, so many changes were made to make the TNW a semi that the rifle/MG is now tempermental. Nevertheless, it looks great at the range and with a lafette mount is quite accurate.
Marstar still has some, but without the bolts. As soon as TNW sends the bolts (has already taken a year) more will be for sale. The cheapest I ever saw them was $2700 (Marstar Clearance), usually they go for $3000 and about five have been sold on the forum during the last year.
TNW has fixed the trigger and many of the bolt problems, it would be nice to handle one of there new guns.
Give me a PM and I can provide as much info as you wish (pics, etc.) I know several owners and might have some in's if one does come up for sale.