Based upon the price in South Africa, I'm guessing the 650NK is selling for $5,500-$6,000 in the United States.
Of course, someone can contact one of the dealers, and request a quote.
I wouldn't be surprised if you can use Kawasaki parts in that engine. If you can get the other parts from Taobao (plastic, et cetera), you shouldn't have too much trouble supporting the bike, especially since it has an established dealer network.
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Spud
"Never argue with an idiot. He will drag you down to his level, and beat you with experience."
Mark Twain
2015 Zongshen ZS250GY-3 (RX3)
2006 Zongshen ZS200GY-2 (Sierra 200)
2005 Honda XR650L
2004 Honda CRF250X
1998 Kawasaki KDX220
Mods made to my Zongshen ZS200GY-2:
http://www.chinariders.net/showthread.php?t=6894